Well i think the tube amps you can get around 400 bucks in Singapore now are
Epi Valve Junior
Blackheart Little Giant -Yamaha at tamp can demo
Laney LC15 (that's pushing 400)
Blackheart doesn't have a drive channel though. Epi is just one knob..
There seems to be an increased interest in cheap tube amps these days. Peavey has the Valveking 8, Fender has Champ 600, Crate has its V5 (is V5 avail in S'pore? who's the official crate dealer?)
Those amps aren't easily available locally to my knowledge though.
You might be interested in getting an attenuator like the THD Hotplate from TY to help get Power tube saturation from these low wattage tube amps at a usable-at-home volume.
Alternatively, head to ax84.com and DIY urself.. anyone know roughly how much THAT would cost?