where can i buy cake or card templates to make sneaker, liquor bottle, purse cakes, etc?

AHave you tried putting "sneaker cake templates", "purse cake templates" etc. in the Search box at the top of the page? Or in Google?

Go to wilton.com and look along the left side for the "pattern locator" button.  In there they have thousands of patterns to download for free, and their search box does a pretty good job.