I'd check out craigslist to see if you can find any used lens before diving in for a brand new one. I found my EF 75-300mm III USM glass on craigslist from a professional photog who was selling it because she had bought the newer version. Picked it up for $80 :thumbup: . It's not a "OH MY GAWD ZOOM IS ULTIMATE" lens but it does the trick and didn't force me to become poor.
TLDR check for used, properly cared for, glass in your area.