What's the difference between cheap/expensive?

Specifically this:

600W Photo Video Studio Umbrella Continuous Lighting Kit Portrait Photography | eBay

vs this:

Westcott Basics LED - LED - Lighting - Shop

sans the lightbulbs.

Is there any real difference? They both have umbrellas and stands and light socket + bulbs

I was thinking of getting the cheap one and adding expensive lightbulbs, what are your thoughts on this?

In 2017? - Go ahead!

The Westcott light sockets look made to handle significantly hotter Tungsten bulbs, which might have justified their price, while those were en vogue. With LED substitutes at hand I'd be happier with the cheap counter parts that come with ultra handy cold shoes that allow mounting inexpensive flash guns into the same umbrella.

I know little about sub-variants of "inexpensive Chinese lightstand". What I encountered seems to do the job. They are somewhat portable, if that is what you desire: Get it!

Clarifying: So far I slept dry and happily in similar inexpensive Chinese tents. A biker buddy with hiking allures swears on more expensive lighter more compact alternatives. I am sure they come with better poles etc, but a cigarette burns a nasty hole into each of them. For a professional grade fixed studio installation you might fancy heavier stands on wheels. To carry the kit on a motor scooter you might look into ultra lighter alternatives. Each to their own and you'll be hopefully able to get started with what you get, especially when there aren't too many kids, drunk and visually impaired folks ready to trip over / run into your stands.

In the long run I do recommend switching from continuous lighting to flash for your exposures. It is really amazing how flash freezes your subject in (potential) camera shake and not easy to squeeze safe 1/500sec out of lightbulbs. - Umbrellas eat a lot.

Disclaimer: I did not use any light socket you linked, so I can't tell how long they might last if they really hold an umbrella or if it is possible to overtighten screws to break them....

Cheap or affordable LED lamps aren't really fit for purpose yet, IMO.

Their efficiency is around the same as the older CFL "curlie-whirlies" and so they offer no real advantage apart from being more techno-hip and hyped than CFL lamps.

That Wescott blurb tells almost nothing about their LED lamps. 500 watts? No! That'll be their incandescent (tungsten hot lamp) equivalent output, which is quite weedy. CRI 95 - fair enough, but what's their colour temperature?

Any company as reluctant to state hard and fast specs really doesn't deserve your custom. Look elsewhere would be my advice.

If you want real power and a consistent quality of light, get some speedlights, suitable stands and brollies. Also get a flashmeter. Used flashmeters can be got for very little, and setting up the light positions and power by "chimping" is very easy these days.

Learn your basic portrait lighting positions and you're halfway there - clamshell, butterfly, rembrandt and loop. The other half is basically balancing your key, fill and any hairlight or kicker.

Two softboxes or umbrellas aren't the best start for lighting though. You need one fairly hard, unmodified, lamp for facial modelling, while the soft light is used for fill.

The problem that I have with ALL of those kits that use a CFL/coiled lamp is, there is more light going to the side than into the umbrella. This makes it very hard to control the lighting on the subject. YOU want to be in control of your lighting. In place of the coiled lamps, I would use a reflector flood lamp, to keep most of the light inside the umbrella, where you can control it. And there are reflector type/style LED bulbs

As Joe said, I would get at least one light that is HARD.

Hard and soft lights are different tools in the lighting tool box, and like a carpenter or mechanic, the correct tool should be selected based on the job/shoot.

Because sometimes, an umbrella is NOT the right lighting for a particular portrait.

IMHO, using umbrellas is an easy way to avoid the work of learning to control the lighting. You get a generic portrait lighting, but nothing special.

As was mentioned, the other problem is color temperature of the bulbs, and they must all be the same.

The good thing about continuous lighting is that you can easily SEE the lighting effect. With a flash (without modeling light) you can only see the effect after you shoot. So continuous light is a decent learning tool.

Personally, I went with a pack+head studio strobe. And used ones on eBay are not that expensive compared to what you are looking at. You just have to know what you are looking at. But studio strobes are a different animal than continuous lights.

Just to add a bit to what Gary said about umbrellas. Basically a shoot-through or open white umbrella is a light spreader. Yes it gives you soft light, but it also scatters light everywhere else around your studio, and this makes it difficult to control the depth and "quality" of shadows.

Personally I prefer to use softbox-brollies like these.

I love these things. They're cheap, easy to use and don't waste light by scattering it in all directions.

A few years ago they came on the scene out of nowhere and were available all over the internet for peanuts. Their availability seems to have shrunk and the price risen, but they're still cheap enough to consider disposable. Although I'd say they're indispensible!

Why didn't I notice that the umbrellas are shoot through, not reflecting umbrellas?

Something else to replace.

. . . I was thinking of getting the cheap one and adding expensive lightbulbs, what are your thoughts on this?

If you are thinking about Lighting for Portraiture: then don't buy either, There are many reasons some already outlined above and I think that the main reason why the term "real power" was used, is because, typically, when making Portraits with Continuous Lighting the Shutter Speed is the relevant controller of arresting (stopping) Subject Motion Blur and also sometimes Camera Shake Blur.

So - when using Continuous Lighting we would typically need to have enough "power" in the lights to allow a Shutter Speed around 1/250s. Then of course we have to think about Depth of Field and that is controlled by the Aperture. Not all Portraits that we make will have a shallow depth of field and at time we might need to use F/8 of F/11, for example for a group of 4 people and a dog in a family shot. Sometimes for a couple or a single subject we might want to use F/8; also if we are using a relatively large maximum aperture zoom lens, we might want to stop down that lens to F/8 to ensure the best image quality.

Then - considering that we might be using F/8 and 1/250s (or thereabouts) for some of our portraiture - we need to think about enough "lighting power" to allow us to use a lower ISO - the bottom line is, my experienced guess is that with either of those two lighting sets you'd be up around ISO 3200 to allow that range of Aperture and Shutter Speed selection (noted that I didn't research the actual Light Output of the two Continuous Lighting sets in the OP).

However, even the less expensive third party Hot Shoe Flash Units (aka "Speedlites") will have enough power to allow you to use a good range of Apertures, at the lower end of the ISO range.

WW