Your options are
a) Get a shitty stack new. Behringer, Crate, Marshall, Line 6, and Randall all have an offering in the price range. None of them are very good or really worth the money you'll drop into them.
b) Get a mediocre stack used. Maybe a used Mesa/Marshall/Avatar 4x12 cab and a crappy head?
c) Save up. $800 will get you a new Avatar 4x12 cabinet with $300 left. save up another $3-500 and you can get a Peavey 5150, Line 6 HD147, Mesa Single Rectifier, Laney GH100Ti, etc.. there are a lot of good tube amps that go used for under $1000.
Try hard to get a good cabinet. Avatar makes great cabs for very good prices ( avatarspeakers.com ). $500 for a 4x12 loaded with your choice of speakers shipped. A good cabinet willl be something you can keep as a part of your rig for practically forever, but heads can come and go fairly easily.
If you buy a shitty Crate, Marshall, Behringer, etc. stack new, remember you just threw away however much money on stuff you're going to want to replace with new stuff anyway.