Heh. I'll also add in a few bits for folks who don't go the Gusgen route. Dangruf Wadi will get you to 24th, solo. Valkrum or Gusgen can take you to 30th solo from there and your subjob items for the quest in Selbina.
In town, you'll see an "Artisan Moogle". Talk to them. Get a Mog Sack. Voila, +30 space for stuff.
Furnishings (in the Auction House and the occasional shop) have "Storage"- if they're put into your Mog Safe in your Mog House and then placed with the "Layout" command, you'll see an option called Storage become active in there as well. Effectively, you can convert one space in your Mog Safe into many spaces of storage (max 80).
When you're experienced enough, you'll make it to the central city, Jeuno. Jeuno is MUCH MUCH more populated than the three starting cities, and full of ways to get you into the other big cities- Aht Urghan and Adoulin (much more the second), teleports to get around the world, and the openers to many of the expansions. Lower Jeuno has a goblin-run shop with quests that will expand both your inventory (the so-called "Gobbiebag" quests) and your Mog Sack (after each inventory expansion, talk to an Artisan Moogle to get a matching expansion for your Mog Sack for free).
Jeuno also starts the Abyssea expansions. Experience points being a problem rapidly vanishes after those areas, replaced by getting level cap quests done.
http://wiki.ffxiclopedia.org/wiki/Limit_Break
Read up on these. And note that the fossilized items and seasoning stones for the level cap to 99 will be VERY inexpensive to get your hands on during the login campaign that starts VERY soon.