Agreed, straight stitch and zigzag are all you need. It doesn't even need to be very powerful since ultralight materials are thinner/lighter than most clothing and certainly less than traditional camping gear.
I would suggest looking on craigslist for a used, non-computerized, totally mechanical sewing machine, but not an antique (made before 1950?) Look for one with a traditional bobbin, not a 'drop in.' Get new needles and do a cleaning and lube job on it. Try it out, if it doesn't stitch well, check the thread tension, both top and bobbin. If it still doesn't then it may need a trip to the shop.