Responding to your questions in order:
1) You can set up the product using Variants to offer the buyer a choice of license terms at different prices:
http://www.e-junkie.com/ej/help.variants.htm#variants
In case you will be using our Remotely Hosted Downloads feature to deliver a file stored on your server rather than uploading the file to us, note this technicality for products using Variants:
http://www.e-junkie.com/ej/trouble.downloads.remote-variants.htm
If you would prefer to set it up as two separate products, you can use the "Package files from other products" setting to have a product issue download links for a file you already uploaded for another product:
http://www.e-junkie.com/ej/help.package.htm#bundle
2) This help page explains how to issue generated license keys with your product:
http://www.e-junkie.com/ej/help.keygen.htm
3) After the buyer finishes checkout and the payment processor confirms the buyer's payment was good and completed, we grant the buyer access to a unique thank-you page we generate for each transaction, where we automatically present the buyer's unique download link(s) for whatever item(s) they purchased. These links expire after the number of Attempts or Hours (whichever comes first) that you specify in the product settings. This help page explains how to customize your thank-you pages:
http://www.e-junkie.com/ej/help.custom.thankyou-page.htm
For instance, here's a customized example thank-you page for an order with multiple items:
https://www.e-junkie.com/d/?t=jg-l5rooge0092d567&d=66ac3&c=fup
We also send the buyer a thank-you email message with a link to reach the thank-you/download page in case they did not proceed to the download page after checkout. This email would include the license key for products that issue one, and you can also optionally display the key in the thank-you page, as explained at the help link above.
4) E-junkie is not a payment processor, so we do not handle any actual payment funds at any point. Buyers would pay directly into your chosen payment processor account, such as PayPal. In order to use our shopping cart and other features, you would need to have an account with at least one or more of these independent payment services we support:
http://www.e-junkie.com/ej/help.payment.processors.htm
5) This help page explains our built-in affiliate system:
http://www.e-junkie.com/ej/help.affiliates.htm
Buyers would pay you directly for the full purchase price, while our system calculates any affiliate commission earned in the background. You would then be responsible for paying out commission earnings to your E-junkie affiliates, typically on a monthly lump-sum basis. See the "Pay Your Affiliates" section at the help link above for further details.
6) Once you set up your products in E-junkie Seller Admin, we provide you with ready-made HTML codes for your cart buttons. You would simply copy the codes from us and paste them into the HTML source of your own Web site pages, wherever you want our buttons to appear among your own layout, text and images.
Each product has its own, unique Add to Cart or Buy Now button code. You also have View Cart code that is unique to you but the same for all your products; just make sure you paste at least one complete block of your View Cart code on every page that has any number of Add to Carts. These help pages explain more:
http://www.e-junkie.com/ej/help.buttons.cart.htm
http://www.e-junkie.com/ej/help.buttons.buy-now.htm
Our system is designed to be really quite straightforward to configure and set up, and you have a fully-functional 7-day free trial period which begins as soon as you register for an E-junkie login. Our Getting Started help page is a good place to begin setting up your E-junkie service:
http://www.e-junkie.com/ej/help.sell.htm
