how can ı add radio button to checkout page

1-İ want to add radio button on checkout page.and mail (which is send to administrator to show what he buy) containinformation which is chosen.
2-secondly if he or she buy product over 100$(for example) it is possible to change shipping fee to free automatically?!?
3-it is possible (and if possible how) to show product photo bigger or pop-up when over the mouse

my site is www.cookyskurabiye.com

1. You can do that by creating a custom field of the table "order" (business edition) via the menu Display->Custom fields.

2. Yes. Just create a manual shipping method with a price of 0 and a minimum price of 100. Then, set a maximum price of 100 in all your other shipping methods.

3. You can do like that:
www.hikashop.com/en/forum/4-how-to/42708...-product-images.html