Good beginner tube amp suggestions

Assuming you're looking for an integrated, I'd second Celtic66's Jolida rec for either the 1301 or 1501. They're both hybrids, but as such are a great and affordable way to get into tubes. I owned a 1501, loved the sound and would have kept it if I'd bought the remote version and if it had a headphone jack. It responds well to tube rolling, and since it uses only two 12ax7s you can tune the sound to your liking rather inexpensively. If you want a full tube amp, a Cayin A50-T is at the top of my own list right now: incredible transparency, dynamics, bass, air--and for a great price at $1300 new/$900 used. For the money, though, the Jolidas are tremendous bargains and frequently show up here used.

I'd go with a Rogue tube amp, they average 650 to 750. Very robust, lots of power and can handle a wide range of speaker types so you can try other speakers in the future if you want.

Don't forget Primaluna, whether integrated, stereo
or monoblocs, they're excellent. I've got the 6s
if you'd like to discuss.

If your system will work Ok with 20WPC, the Antique Sound Labs Wave AV-25 DT (or the older AV-20) is a nice choice. They cost $700 for the pair (monoblocs) new, but could be had for much less used. I've used the AV-20's in an office system for a few years, and they have been perfectly reliable and very nice sounding.

Sophia baby electric was what I tried first - $350 used, but it provided a LOT of what I get through a much more expensive amp now.