If one is just starting to look into tube amplification, there is probably no better place to start than with an EL 84 (7189) amplifier. This tube has a lively, punchy sound and is on the warmer side. Most people go for tubes for that warmer sound (elevated upper bass/lower midrange) but sometimes that means a more murky or mushy sound. Most good El 84 amps avoid sounding that way. It must be one of the easier tubes to work with because most lower cost amps that are not trying to push out a lot of power employ this tube.
I no longer own an EL 84 amp and I am not familiar with currently manufactured amps using that tube type, so I have no specific recommendation. I suspect that under $1,000 would be a challenge to find ANY well-built new tube amp because decent transformers and other critical parts are not cheap. As for used, someone new to tubes would probably need some help finding, checking out and and refurbishing, checking tube bias, etc. But, if you go the vintage route, and spend a bit more than $1,000, there are amps that are 60 years old or more that would kill most modern amps when used with reasonably efficient speakers. An example would be the Eico HF-81 and the Scott amp mentioned above and the Scott 299A or B. The much coveted Scott 299C runs an entirely different tube (7591, a more powerful tube) and it is killer good too.
There are a few other tube types that offer similar sound that i also like a lot, such as the 6L6 and KT 66 tube. These are not particularly popular because one can manufacturer much more powerful amps using the same basic parts if something else, like the KT 88 or EL 34 tube is used instead. But, to me, the 6L6 tends to sound better (not as hard or brittle sounding). You can actually get a new 6L6 amp under your price range in kit form if you, or someone else, builds it. Elekit (Japanese) offers the 8200 model that can be bought for around $800 without tubes. They offer built models at a higher, but still very reasonable price. They also offer sensible upgrade options with their amps. I have not heard their 8200 amp, but, I've heard other models from them and they are quite a bargain.
