I'd recommend a plastic case like X-treme or Cigar Caddy. Granted they don't look "cool" like a wood humi, but they work great. I bought one (X-treme 15); they have a little piece of florist foam in the top that you wet with 50-50 solution initially and replenish with distilled water or 50-50. I keep a little hygrometer in mine and it stays between 60 and 70% RH. If you only add 50-50, eventually the RH will fall as all the water gets replaced. Throw some cedar scraps in so your cigars get a little feel of wood, if you like, and take out the foam inserts.

I bought a cheap wood humi and can't get the RH up past 60%--they probably don't seal as well as they should.