Maintaining a pool that size is super easy (looks to be about an 18' x 4'), and not expensive at all.
One of the most important things to do is take a water sample down to your local pool supply store to be tested. While there are all sorts of tests kits available now for the home user the tests they run are way more precise, and they can explain the importance of everything. Most important tests they will do are:
-Alkalinity (If it's too far off your ph will fluctuate like crazy and you'll be constantly chasing it)
-Calcium Hardness: Too low and it'll corrode any metals it touches, too high and you'll get scale and cloudy water.
-Cyanuric acid : Stabilizes the chlorine in your water to keep it from burning off in the sun
Some other tests they'll do:
Dissolved solids: Water can only hold so much before you'll have to drain and refill
Metals: Iron and copper (mostly from people filling their pools with well water)
Once tested they will recommend chemicals needed to balance your water. On a pool that size it'd probably be about $50 - $75 depending on how bad the water is.
Once the water is balanced it's pretty much a matter of chlorinating and circulating the water.
Put the pump on a simple timer to run a few hours a day, add an automatic chlorinator you fill with slow dissolving tablets, and test ph & chlorine once a week. It'll pretty much be hands free maintenance for a week or so until the chlorine tablets are gone and need a refill.
Having a pool to jump in when you get home on a hot summer day is awesome!
Like others have said, just do a little research, and you'll learn a lot. I worked at a pool supply store for a few years in my youth, and did thousands of those water tests. Once your water is balanced it will be trouble free for years (depending on how much you drain out at the end of each season).