If you want to venture on your own, you can try:
1) Create your digital comic book... show some samples and offer to email the PDF, CBR, CBZ or ePUB formatted comic by email... once you receive the Paypal payment.
2) Offer your book for free online and offer a soft cover or hardcover signed printed copy mailed to the customer... once you receive the Paypal payment.
3) Make a physical copy of your book ( example Apple's Book Service: http://www.apple.com/ca/ilife/print-products.html ) and show it off, get orders for print and digital... you know the rest.
4) Set up a store on eBay to offer your comic books.
These are some ideas... You could possibly come up with more interesting ways on your own.