Once or twice a year I sing at a benefit and I am asked to bring my own amp. I've borrowed a few, but am ready to buy a cheap one for those rare occasions. I saw one for $59. at a local music store and wonder if you catters have any comments about cheap amps.

This one sounds okayish; not great but serviceable- and it's small and light enough for me to lug by myself. (which is important to me) I'm just wondering if a cheap amp would harm the guitar (Martin ) and any recs/brand names to look for and/or avoid that you may recommend.

btw the store owner said I'd have to purchase a cord for the amp separately. Was he s******g me? I have an old cord lying around somewheres; would that do?