>Was thinking of trying the program that this site it using instead - www.wizardscupboard.com
Yikes, that site screams 2001. Looks like it hasn't been updated since then. Even the footer says, "This site is best viewed at 1024 x 768 display running Internet Explorer 5 or higher Site structure originated from OSCommerce"
Maybe an established site can get away with that but not someone new.
Magento and BigCommerce are also very large established platforms that might work.
I hate to be the bearer of bad news, but if you're as rusty with HTML as you say you are, then you might not be the best choice for building something that's going to be part of your company's public front.
I suggest contracting a developer to do it. There's plenty of affordable talent crawling around Reddit right now, in this very sub.
What you may wish to do instead is to look into using a pre-build cart system. Most of the hard work is already done for you, they are fairly easy to set up, and all you have to do after that is to fill up the catalog. There may be minor things to take care of, such as including your company's logo, but that should be easy to do in the admin section.
I suggest going the cart route, because 1) It's less time and effort for you to set up and maintain, and 2) You come out looking like a genius for going above and beyond expectations.
I suggest having a look at some of the more popular cart systems, such as Magento, or OSCommerce - I'm not familiar with Magento myself, but it's very popular, and well supported. OSCommerce, however, I have used before - I suggest going with Magento or better, because OSCommerce is a pain to customize and isn't as sleek as Magento or others.
Good luck in your endeavor!
I have looked at the source code for both platforms and from what I can see Magento is far more complicated than Oscommerce. It is more modern and has far more features than Oscommerce as a fact.
In fact I have outgrown my Osc store and I am planning to migrate to Magento.
As for the SQL injection attacks, you right it is susceptible but there is a free anti-XSS contribution available to prevent attacks.
Magento is overkill for a startup shop as it's very complicated and requires dedicated hosting
If you want a start-up shop try Oscommerce v2.3.1. It's free and you only need some shared hosting using LAMP setup (Linux, Mysql, PHP).
This enables you to upload products to your website, require customers to enter their personal details and complete checkout. The payment option you will set is "Cash pickup from store" so you don't need to bother about setting up card processing accounts.
example webhost e.g Bluefur
It is much easier to customise Oscommerce yourself and there are loads of free contributions available to change the store functionality
Take a look at OSCommerce.
It's open source, works decently for a free package, and there are tons of hacks and tweaks in the forums.
Then you charge your client whatever you want. I usually bill by the hour.