the 135mm F2.8 can easily be found under 100 euros, the point is that im in Europe and with shipment + customs duties sometimes the price can go up about 2/5 of the original... I tried to look in second hand stores and photography stores but or they are in good condition and are way more expensive or they are in a lousy state...
one more question: using a tripod and photographing still-lifes cannot the lack of speed of the 3.5 be overcome? I understand the advantages of the 2.8 quiet well, and probably that's the one I will buy, but still, the price diference is kinda big