As harsh as it may come accross, cloudrck is 100% right. If you can't poney up for a decent SSL cert (or use StartSSL and get them for free, with awesome security still), or don't know how to get a simple SSL cert to work on your domain...then you need to be learning how to do that.
If I go to someone's cart, where I have to input my payment details...and there is not https in that address bar...the site gets closed and I move onto another place that cares about the security of my information.
Forcing http when you are offering any type of online service and intentionally not using https simply because you do not want to pay for a non-expensive certificate is definately not the way to start in this industry.
Not trying to be rude, just trying to keep you from falling into trouble.