For my first amp, I used a Guitar Fuel Tonemonster MAH5.  It works great!  Sounds good.  I like it.  Costs $44.95 plus shipping.  All good.

But, for my second amp, I started looking at the features I wanted and how I could get them under $100.  Here's an i

dea: check Craig's List and Guitar Center for used low power amps and hack the electronics from one of them to give me the look I want.  

Here's the spec on what I picked up: 15 Watts, includes 6" speaker; controls for volume, treble, mid, bass; drive circuit and reverb; phones out (*1/4"); and power switch.  The price: $19.

One the down side, can't run it from battery.  I need a fairly large cigar box to fit the electronics in, but I think I have just the one.  I will post more when I start on the mods.  

So, if you are looking for effects modeling for your CBG, you might find a used Fender Mustang Mini or something and give it a makeover.