I have a Yamaha BBT500H head that when new cost me under 400€. It requires two 4 ohm cabs to get the most effect (500W) out of it though.
You should be able to find one of those pretty cheap. Mine has never failed me, but I wish it had less sound shaping possibilities. It also has an audible hiss said to come from the class D power amp when using it with an active bass and the tweeters are on. It's not on the line out.
The three best features in it are IMO:
1. Light, only 5kg
2. It's a good sounding amp despite the hiss (I don't use the tweeter so the hiss is no problem for me)
3. The price.
The three worst features:
1. Too much sound shaping possibilities. You get lost easily.
2. Headroom with 4 ohm load. With 2 ohms it has always been enough for me.
3. The hiss.
A fellow TB'er sold his because it got too hot acording to him. Mine also gets rather warm, but as it has never failed me even though I often push it pretty close its limits, I have ignored the heat it generates.