Jackets & Trousers, and types of camouflage

There are over ten or twelve types of camouflage, ranging from those used by the various national military services of several countries, to civilian makes and designs. Overall, you need to consider the main use that you'll put it to: are you playing in a woodland, open, or urban setting? Do you want to be different, or follow what most others will wear (a team uniform, if you like)?
The most common patterns of camouflage on clothing, that I regularly see on UK Airsoft Skirmish sites, appear to be (in order of appearance, and from left to right):
BritishDPM
AmericanWoodland
GermanFlectarn
SwissAlpenflage
FrenchCentralEuropean
I'd suggest, for cheapness, that the various form of British DPM camouflage clothing are probably your best choice; I say this for two reasons. One, it's plentiful, there being loads of it on the surplus market, and two, that due to this abundance of clothing in the surplus market, it tends to be cheaper, like for like (quality-wise), than different camouflage patterns.
Whatever pattern you choose, get a jacket and TWO pair of trousers at the minimum - you never know when you're going to need that second pair - and likely as not, it'll be a ripped pair of trousers that leaves you cursing your rotten luck, and wondering why you didn't follow my advice, and get TWO pairs of strides!