[bombloader]

So here's the scoop. I'm getting tired of running down to the gas and putting quarters in air machine every time one of my tires is a little low on pressure. So I'm looking for a good inexpensive air compressor. Also, this should help me get closer to the "cold" pressure recommended on the sidewall. I've thought about three options.
1-Buy a full shop type air compressor. This would be the most versatile option, allowing me to run air tools if I need too. Also, would do the job pretty quickly. Cons, really expensive for even a small one unless I get one used.
2-Buy a small cigarette lighter plug version. This is a lot cheaper, $40-50 at NAPA last time I checked. Another benefit is that its portable, in case I need to air up a tire in the middle of nowhere. However, probably quite a bit slower. I've got 31-10.50 tires, so I don't want something that will take forever on one tire.
3-Buy an air tank, and fill it up periodically at the gas station. Cost, probably similar to the above option. Not much to go wrong with it, and might be fairly quick at topping of tires if the pressure is high enough. The downside is of course I've only reduced my dependence on the gas station for air, not eliminated it. Also, not sure how much pressure those gas station machines can make, so if I buy a tank it won't do much good if none of the gas station machine will fill it to the highest pressure it can take.
Any thoughts guys?