With that budget your best bet is going to be looking at what's available used. Line 6 fits that range but I've used a combo from them for a lot of stuff and they're not as versatile as you might think. They're definitely not a tweaker's amp.

When comparing wattage with price keep this in mind- 50 watts is not half the volume of 100 watts. 10 watts is half the volume of 100 watts, the difference in numbers is the number of distinguishable increments. If it's a good amp (by good I partially mean tube) you'll be able to get by with a 30 watt amp easily.