Other than using a humidor, what other ways can I keep cigars fresh?

Depends on how long you plan on keeping the stick before smoking it.

Double bagging it in a ziplock type bag, sucking all the air out will keep it smokeable for a week or two.

You could always use an airt/water tight container like a Rubbermaid. Humidification would not be as crucial. Make sure the container isn't overly large.

Do NOT use the moistened sponge method for humidification. Tap water will cause bacterial growth. More importantly, with tobacco being hygroscopic, it will continue to absorb moisture and make the stick unsmokeable. If you do use a humidifier, use cigar juice which is a 50/50 solution of propylene glycol and distilled water. PG will keep the relative humidity in check and is an anti-microbial. You could also use a Boveda pack or DryMistat tube.

get an off cut of lead sheet anf make a box with a tight fitting lid. Keep it in a cool and dark room. It works. This is what cigar merchants did before humidors.

Honestly, without a humidor, I would not bother buying more than I would smoke in a week.

At less than $40 for an inexpensive humidor, it pays to get one. With a decent cigar running at least $5, it does not take too many stale cigars to justify the price.

Here's one like I have

http://www.amazon.com/Elegant-Cigar-Glass-Top-Humi...

I used an old cigar box. I took a sponge and cut it into a piece about the size of a Zippo lighter. I then kept the sponge moist. A friend of mine did the same thing with a sponge, but kept his cigars in a Tupperware container. I hope these ideas help.