When you have all of the needed badges, you will level up and get seeds and tinkapoints, as well as some new features.
After an update on tinkatolli in Early October 2011, Level jr. became the default level. To get to level 1, you need to have the Berry Good Start badge, the Jr. Collector badge, the Jr. Explorer badge, and the Teleporter bage (50 blings). You get 600 seeds when you level up.
Level 1 used to be the default level. When level jr. released, you had to work to get to level 1. When you get to this level you can start the first (and only) quest.
To get to level 2, you need the Jr. Builder badge, the Jr. Seeder badge (getting 1000 seeds), the Online Mover badge, and the Flapper badge (100 bling). Your rewards are 250 tinkapoints, 500 seeds, and a set of new hairstyles.
To get level 3, you need Jr. Scrapbooker badge, Sorter badge, Sea Glass Hunter badge, and the Woot Wiggle badge (500 bling). Your rewards are 250 tinkapoints, 500 seeds, and a set of new mouths for your tinka.
To get to level 4, you need the Collector badge, the Online Giver badge, Offline Mover badge, and the Cassi Flower badge. Your rewards are 100 tinkapoints, 500 seeds, and a short-cut to your tinkapad. When you get this shortcut, whenever you get your player card up, an extra button will be added, saying "Take me home".
To get to level 5, you need the Asimov badge, Online Maker badge, Offline Giver badge, and the Jumper badge (for 1000 seeds). Your reward is 1200 seeds.
PLEASE EDIT THIS SOMEONE.
Level 7 is currently the highest level available. To get level 7, you need to get the Trader Tiro badge, Offliner badge, the Onliner badge, and the unavailable Tinkertown Rock badge. Your reward is to be able to make a second tinka. You get 100 tinkapoints and 300 seeds to go with it.
Level 8 is currently unavailable due to the unavailable Junkey badge not being available yet. To get to level 8, you need to get the Super Jumper badge (3000 bling), the Junkey badge, The Tinka Fair badge, and the Trader X badge. Your prize is that you get a THIRD room to your tinkapad.