What speakers? Sensitivity rating? How large is your room? Type of music? How loud do you listen? (More powerful tube amps are generally more expensive.)
Do you want a vintage made-in-USA amp, or a Chinese amp?
Do you want quality, or are you obsessed with “scroeing”?
If modern Chinese amp, I can’t help you. If you’re obsessed with “scroeing”, I can’t help you.
If you want a vintage made-in-USA amp, then the amp should be professionally restored. (Beware of “flippers” who aren’t professional techs, who replace a few easy-to-reach, cheap capacitors, and “reform” the power supply caps, and claim the amp is “restored”.) If you pay a professional tube tech to perform the restoration, or buy a competently restored tube amp, the total price of admission (amp + restoration) is about $1k. You can occasionally get lucky and find a nice restored amp cheaper, but IME (and I own more than 2 dozen vintage tube amps), the price of admission starts at $1k. If you want a pair of professionally restored McIntosh MC30s, then the price of admission is more than $3k (and well worth it). And, you can spend much more than that …
OTOH, if you are a competent tech, and an entry level power amp (e.g., “console pull”) is suitable (no phono stage or controls), and you enjoy “dumpster diving” and/or shopping estate sales, you can get into tube amps for less than $1k (if you don’t account for your costs associated with your search for a “scroe”).