Cables can be expensive in general and are a topic themselves, but rest assured that you can find cheap ones, especially at online stores.
Will you just keep the TV on a stand and flip channels from a couch? - Or are you planning on connecting all kinds of things to the TV, like a gaming console, computer, Blu Ray/DVD player, sound-system, or others? If you won’t do too many things like this you won’t need to pay much attention the different connectors at the back of the set.
At the very least, you’ll need the standard coaxial TV cable jack to connect straight to your satellite or cable box while making sure the TV has a set of built-in speakers. If you plan on using your TV with other peripherals, you will need a few HDMI and RCA jacks. A digital optical audio out (TOSLINK) would be nice or may even be necessary to connect audio to your sound system. Maybe even a DVI, VGA, and USB jack for connecting a computer and USB peripherals.
What is important is that when you browse the aisles at the retailer or online store, make sure you examine the back of the prospective TV or look at its specification sheet to identify what cable jacks it has. Do they suite your needs? This is an important question. Otherwise, you may end up with a large expensive item that won’t let you set things up the way you want. You may not be able to use your entertainment and computer equipment and will have to repackage and return a large heavy TV to the store at your own expense(time, money, and effort).
If you’re surprising someone else with the TV, try asking that person non-obvious questions about what they’d do with a big flat-screen and if they’re into sound systems and computers. This may reveal what kind of cable jacks you need really make the ultimate gift.
Some TV’s only have one audio OUT so make sure your sound system has the same connector type IN. Also make sure the TV has compatible video inputs.