I haven't yet figured out how to add my custom products to price lists or galleries.. 

Also, is there a way to have a public 'store' or page with custom products... a place where clients can pay for services such as their session fee?

I'm new, bear with me.  Thank you! 

: ) Didi

Welcome Didi to Zenfolio!

First you have to create your custom products on the selling page. On the left there is a section "My Custom Products" click through Settings, Collecting Payment, create your Shipping Methods and finally your custom products.

Then you are ready to select Price Lists. Create a new price list and on the pricelist page you click on Add Product. A popup window appears where you can choose which product you want to add. Amoung these there should bewill a section with your custom products you have created before. Choose one and it be added.

Hope this helps a little. If not keep asking here.

Regarding services as custom products and session fee there is a valuable thread over here http://forums.zenfolio.com/forums/t/3313.asp