Build an Online Store

I need a plugin or widget making that I can add onto website, I need it to be like a custom tshirt plugin although the product isn't always tshirts so I want to ability to change the product. I want the user to be able to write their custom text, I don't want them to choose a font or a size (I want to predefine the fonts and colour set ups for them). Then I want the checkout function also to work but I don't want to display a shopping cart on the site. Really urgently required.