The standard E-junkie cart buttons should work fine on the Blogger/blogspot.com service. You will need to use the HTML button in your Blogger editor toolbar.
You may also wish to paste your E-junkie View Cart and Script code into a common template area (header/footer/sidebar), so it gets included in every page automatically; this Blogger help page explains how to Edit HTML for your blog template.
For best results, you may need to save your posts directly from HTML mode after pasting the code, rather than switching back to visual mode before you save. See the placeholder tip here to help you find where to paste the button codes in HTML view.