Configuration of the e-commerce site – you need advice!

I am creating an e-commerce site for a friend who sells jewelry. The site will present perhaps 100 products eventually with different personalized options such as color, stones, types of chains, etc. I need help in the following problems:

1. Shopping cart. Some have recommended Zen Cart (free) and others have recommended paid cars like Americart. And there are some two hundred more. I need something that allows options when paying: will Zen Cart work for this? And with the free Zen cart, do I need to buy my own private SSL?

2. Obtain an internet merchant account. Is this done better through the individual bank?

3. Payment gateway account. What will work and be safe without breaking the bank of my friends? Do any of the shopping cart services also provide this service?

4. Hosting. My friend's site will be a fairly small volume. Will an affordable shared hosting plan work like the $ 6 / month plan from hostgator.com? I see that hostgator has an e-commerce plan of $ 15 / month, but it seems that I will not need it if my shopping cart provides private SSL.

Thank you!