Manual or DSG? If manual, you will likely need a clutch soon after going stage 1, which will quickly blow your 1k budget. There are low torque tunes to try to prevent that, but it's still a gamble. If DSG, it's a good idea to budget for that tune too, which will also put you at our over budget.
If you really want Cobb, buy your AP through a good tuner (EQT, Stratified, etc.) and it will come with their stage 1 for you to use instead of Cobb.
Lastly, use the search function. I know this is the "stupid questions" thread, but this topic has been beaten to death. Tons of info out there already.