Do a search, there are many threads on the subject...
Harbor Freight is a cheap source, Miller & Lincoln are popular brands with others.
NAPA sells Thermal Arc made by FirePower (3-N-1 style is a good starter unit for someone just learning), and Marquette by Lincoln Electric is their higher quality brand but pricey.
I have an old Clark Mig welder. I like it a lot, but they have been out of business for years and replacement parts are harder to find, nothing locally - mainly online out of Chicago. So I buy parts in bulk, but I use the welder 3-4 times per month/year round.
My suggestion is to evaluate how much you will be using it in the future and what you may be working on (metal thickness/sheet metal/aluminum/etc.), buy the best your willing to afford, not the cheapest you can find. You will improve over time, your welder will not... you'll be limited to it's capabilities.