Tickets for the Malaysian Grand Prix are quite cheap, of course you have to pay a lot to get there if you are in America or Western Europe: Malaysia being a great destination as well as Sepang being a great track you may be able to justify it though. There are no General Admission tickets as such but four different general admission hill stand areas 3 of which are about €18 or £15, for weekend tickets that is, the jump up to grandstand seats is a lot though.
The K2 stand is near the start of the lap just after turn 2, to see the cars for the most time though get Malaysian Grand Prix tickets by the slower turn 9: if you want to go for a hillstand though for this you will need a ticket for the slightly more expensive covered hillstand, still only around £29.
To watch cars going through the corners that are the real highlights of the circuit though you will need Sepang grandstand tickets; turn 14, 15 and turns 1 and 2 are undoubtedly the best places to watch: though there is no stand or bank at 14 itself but you can watch from the mall area stands further up the straight. Turn 14 is a tough corner and cars are more likely to make mistakes here, passes may well be setup here though they may not be completed until turn 15 or even turn 1.
Turn 15 is the hairpin before the start/finish straight but also where the pit entry is, Tower 1 on the hairpin usually sells out fast. Apart from the towers at the turn 15 hairpin all other grandstands have screens though none of the hillstands do.
The best value Sepang tickets, for seats at least, may be those in the K1 stand at turns 1 and 2, only about £120 for the weekend you get a great view of the turn 1 and 2 section including the first corner action and plenty of overtaking here during the race. You can even see the pit lane in the distance and turn 4, it may be worth bringing binoculars to make the most of the vantage point though.