I just found this add:
canon 28-135 IS USM used for $300 also he says he has a new one for $350 I wanted to buy a tamron 28-75 or sigma 17-70 do you think I should go for this? or should wait for another opportunity the get the tamron or sigma
P.D. I'm starting in photography and don't have experience that's why I came here for your help I only have rebel XTI and the canon 50mm 1.8 thanks...

