I need a lens, I don't have money

[Dan Fleming]

Dig into that one - there's no such lens. There are a whole bunch of different 75-300mm f/4-5.6 lenses (f/4, not f/4.5, -/+ USM, MkI/II/III, and one with IS.). There are only two 70-300mm Canon lenses - a70-300mm f/4.5-5.6 DO IS USM lens (that's the only one of this whole group that starts at f/4.5, and it retails for $1200, so that's probably not it), and a 70-300 f/4-5.6 IS USM. If it's that last one, that's the best choice of the ones you're considering, if it's in good condition - but make sure it's 70-300mm, not 75-300mm.

yeah, my bad on slapping that .5 in there []

[neuroanatomist]

In that case, get the used70-300 f/4-5.6 IS USM (assuming it's in good shape). IQ will be slightly better than the EF-S 55-250mm, and build quality will be noticeably better, it's 50mm longer, and has USM. The Canon 70-300mm IS usually sells used in the $375-425 range. If you're able to find one that fits your budget, you're getting a great deal! Else, the EF-S 55-250m would be my recommendation.