I use the small affordable ($199) Yamaha THR5 10-watt 2×3″ Modeling Combo Amp. It’s a good quality amplifier with some neat modeling effect to change the sound of your guitar to imitate other guitars. I particularly like it because it’s portable. Mostly I use it with the Boss RC-3 looper. I play a chord progression on the looper and then solo over the changes. Unfortunately, it doesn’t have a mic input. Not so good for singing and playing.
I think a good amp for the money is the Fender Acoustasonic 40 – 40-watt Acoustic Amp. I haven’t tried it myself but I have tried several the older Fender Acoustasonic amps and I thought they were good bang for the buck. Going for $229 at Sweetwater.
I’ve used the Peavey Ecoustic E208 30-watt 2×8″ Acoustic Combo Amp briefly. I thought it sounded good and has many features. It has two inputs that can be used for either guitar or mic. I’ve read several reviews that say they hear a lot of hiss (noise) when you’re not playing. I don’t remember that but I wasn’t really looking for it either.
If you’re willing to spend a bit more money ($349) I’d take a good look at the Fishman Loudbox Mini BT 60-watt 1×6.5″ Acoustic Combo Amp.