How to start an online baking store type thing?

[Jake]

It's possible to crate a simple store site on a free host like Google's Blogger.com and accept payment through Paypal.

There are marketplace sites and ecommerce site hosts that have most of the logistics ready made, simplifying the setup of a catalog and shopping cart. Some estore hosts offer a mini account allowing only a small inventory for free to get you started.

Selling food can be more complicated, many states don't allow the sale of food prepared in an an uncertified kitchen.

The liability possibilities from someone claiming to have been poisoned can be scary, any real food business would have insurance in place to cover such possibilities, worst case, very unlikely possibility, your parents bank account or house could be put at risk.

You might get your feet wet by offering some hand crafted goods on Etsy.com they charge 20 cents per item listed plus 6% of any sales, they welcome kids but require someone over 18 to signup on your behalf.