For ordinary pub gigs, rehearsals and home use, I have an Ashdown EB180-12, decent little amp and loud enough for my purposes. You can find them second hand for under £100. I used mine last night at an open mic with my band and guests. These days I prefer to DI for most gigs, though, sounds good, takes up less space on 'stage' and saves me carrying more stuff to and from the car.
I also have an Ashdown ABM500 and Barefaced Super Twin for larger gigs, but haven't felt the need to use them this year, DI covers everything except informal jams and then the little Ashdown does fine. Beware of buying more than you need!