Sure there are, long as you do not intend to play too loud and your speakers have a friendly impedence curve. Used of course. Assuming both of those are not problems you could probably get by with a 40 to 80 watt job and there are many such on the market. I've used a Sonic's Frontiers SF80 for years - I've seen it on the 'gon for 800 to 1000 from time to time. Good push/pull type which uses EL34's, 6550's, KT88's or KT90's (KT99a's), and to my ears sounds best with KT88's, excellent bass (for tubes), and easy to use. I'm sure there are many others but I've not personally used them. Also, a tad higher than you budget, and with the same caveat about power and without quite the bass impact, the Primaluna Prologue 1 or 2 are quite good as well and even easier to use.
Tube amp question
Are there any tube amp for under $800 that will drive speaker 88db or lower sensitivity? Thanks