A 5 watt guitar amplifier sized 10X14X5 cm, with an onboard rechargeable battery and a clip which allows one to attach the amplifier to one's belt, and only costing $33, including postage? Sounds too good to be true - but there is such a device - the Aroma AG-03M Rechargable Cube Guitar Amplifier. At that price, one can't go wrong, even if the amplifier is a dud.
I ordered this device from DX in the middle of April, and it arrived the other day. Today I brought it home and tried it out. First, the battery had to be charged (with a USB cable, exactly like a mobile phone) - the documentation says that the initial charge should take six hours, but it seemed to be complete after about two.
So I turned it on, connected a guitar - and had my ears blown out. Once I turned off the distortion (this is the default setting), the volume was reduced greatly - a bit too quiet. But otherwise the mini-amplifier seemed to be fine, and certainly value for money. This makes it a fine practice amp (especially as one can move around with it) and maybe a busking amp, but not a performance amp.
As with all devices these days, it is possible to add a memory card. I naively thought that I could record onto the card, but it would seem that the card's function is to play stored songs back through the amp - i.e. turn it into an mp3 player. I don't have a spare memory card at the moment to verify this, but it would seem that one can't play back songs and amplify guitar at the same time - a bad design decision as this functionality would have improved the ability to practice along with music. There is a microphone socket (3.5mm) which presumably works in parallel with the guitar.
I wish I had something like this 45 years ago.
Incidentally, talking about guitars ... I was in a guitar shop the other day, in order to buy pegs from which I can hang guitars on the wall. There was a beautiful 12 string guitar there, apparently a Fender CD-160SE 12-String V-2: this has a good sound and is smaller than I had expected - very comfortable to play. As with all guitars these days, it comes with an onboard pre-amp, which allows one to connect the output to an amplifier (or effects). The price is a bit expensive for the moment (around $800), but I'm hoping to buy it for my birthday in a few months, especially if I can spread the cost over 10 payments (as I did for the guitar pegs and the piano chair that we bought).