Where to begin??
Warm flat beer is 100 times worse than warm carbonated beer in my opinion.
You can naturally carbonate you beer in bottles for about 50 cents. (4 oz corn sugar)
You need a container that will hold pressure (keg) and co2 to carbonate beer. You can use corn sugar in a keg to naturally carb it too. But thats expensive because you need kegs,co2 tank,regulator,connectors, and a fridge to hold a keg or 2.
I use 4 oz of corn suge in most all of my beers and its just about the perfect carb level.
If you use too much you will have guysers every time you open a beer. Cool to watch but not so cool loosing half the beer.
I remember on one of my first batches i tried a beer after botling. Yea, it was flat-go figure!!
1 week and it will carbed enough to drink one usually. 2weeks is almost always mostly carbed(but young). 3 weeks and then another in the fridge makes it good. The cold will help clear it a bit.

And on to mugs in the freezer!! Just a warning, if you ever go to other forums DO NOT MENTION THE "FROSTY MUG!!!!"
O.K., the reason being is that an ice cold frosty mug(or glass) will kill a certain amount of your beers flavor. Thats why the guys drinking light beer love the frosty mug so much, they obviously do not enjoy a true malty beer flavor.

A clean room temp glass rinsed with cold water before you fill it works the best. Or not rinsed as long as its not hot.

Has anyone tried the Fizz Giz at http://www.FizzGiz.com? I keep a bag of the caps in a kitchen drawer. You have to have the little co2 injector (sold separately). But I love the caps and I've had no problem with them. I've pressurized beer up to 60PSI experimentally. It was GREAT! What's cool about it is this... If you open a beer and it seems a bit flat, U-can give it the boost it needs in mere seconds.

You put your homebrewed beer in plastic soda bottles?

Not I my friend...not I.

Plus, I don't see any way to regulate the CO2 pressure on the tire inflator. Unless you like all your homebrew to be super carbonated, this seems pretty useless for beer. Especially for beer in brown glass bottles.

To each his own, I guess.

In regard to maduro44's comment about cartridges for paintball guns being cheaper, I've noticed that WalMart's sporting goods area sells boxes of co2 cartridges 12 and 16 oz that seem to be directed toward the BB gun and paintball gun market. And, true enough, they are low-priced. Take care to note that cartridges and larger tanks alike are manufactured in an extrusion process with a die and a forming plunger. Lots of petroleum based lubricants are used in the process. Cartridges that are NOT STRICTLY FOOD GRADE - which are intended for use in BB guns & the like are NOT WASHED clean of the lubricants. A small amount of lubricant from a co2 cartridge going into the pressure chamber of a BB-gun is probably a good thing. However, if used to carbonate a drink, your beverage can end up tasting like a kerosene cocktail. Best to try to find the best deal on FOOD GRADE cartridges if you use them. There are some links to other sites vending food grade cartridges from the www.FizzGiz.com website.