don't buy your regulator at the welding supply shop.
honestly, the reason why is because they are better than what you need. the good welding supply shops only sell dual stage regulators, which is more than what we need, but what a welder would need in order to make good welds or cuts. we only need/use single stage regulators. don't let this be confused with dual gauge regulators though (a tank pressure gauge and a regulated low pressure gauge).
you can get a new co2 regulator cheap enough direct from micromatic, or find used ones on ebay.
echoing what others have said, try to get the co2 tank used and in test (five year test). the reason being that most welding supply shops will just swap your empty tank with a filled tank that is definitely used. this means you lose your shiny new tank. also, tanks can be found significantly cheaper used than purchasing from the welding supply shop or new online.
if you can't find any used, i believe beveragefactory has new tanks for pretty cheap.
i've dealt with tom on many occasions, and he is an excellent seller. you pay for the convenience of having it all together for you. i find it more fun to find the parts and do stuff myself if it is more economical to do so (sometimes it isn't!).
my suggestion to you is to buy rolls of tubing if you can afford it. i wish i did. at first i thought just buying what i needed would be good, but then i had to keep going back to the LHBS to get more tubing, more fittings, etc. buy in bulk now if you can to save yourself the hassle, especially if buying in bulk cuts down the cost per unit.