A machine from Costco is fine since the return policy is so liberal, but you say he sews already. What machine does he use at home? if it's a fancier machine he may not be happy with such a basic machine. I would skip the Singer. Maybe look for after Christmas specials at a Brother or Janome dealer, they may be looking to unload what's left of the machines they brought in for the holidays. I know most Brother dealers also carry Jukis, they have some good low end machines.
Cari