Definitely check out craigslist. I got my 40g breeder on there for $80 and it came with tons of viv decorations and the uvb fixture, even a cricket carrier and some cricket gutload food
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You can also make a posting on craigslist that you're looking for a tank, I know that's how a member here got her nice big 4x2x2 enclosure
I hear petco (or petsmart? I think petco) does a sale a couple times a year for tanks at $1 a gallon which means you could get the tank for $40, I think the screen sliders sell separately though.
Good luck!