Well quality goes:
White -> Blue (Fine) -> Green (Masterwork) -> Yellow (Rare) -> Orange (Exotic)
So the stats on an Exotic piece of Lv80 armour will be higher than those on a Rare, and in turn higher than those on a green etc.
You can pick up a full set of Green Lv80 gear from the TP for pittance, talking 10-15s.
Full set of Rare around 1-1.5g.
Full set of Exotics around 10-12g.
Then you just have to decide what 'skin' you want, if its normal skins you like (Pirate and the sort), then you can just go nab some dirt cheap armour in the style you want and transmute away.
If you want the karma skins, you'll have to go run around and collect the parts you want, then transmute.
If you want the fancy dungeon skins, you'll have to go run dungeons for tokens, each run gets you 60 tokens. Boots and gloves cost 180 tokens each, shoulders and helm 210 tokens each, leggings and chest 300+ tokens each (can't remember exact amount).
Dungeon armour is already exotic, so max stats, but it might not be the stats you want, in which case you'll need to buy exotic armour with the stats you want, then transmute the look of dungeon armour over to it.
Then there are also the WvW armour sets you buy with tokens you get for kills. And the Orr Karma Armour that is 43k karma a piece (much easier to get now they've added liquid karma to the daily and monthly rewards). Both sets are Exotic in quality.
When you first hit lv80, I'd go snag a full set of Rare armour, and Green jewellery. You'll be set for doing any content with that. Then go pick out what stats and look you want, and start working towards that perfect exotic set