i have installed market press ecommerce and paid the 19.00

i have installed market press ecommerce and paid the 19.00 but i don't see any themes that are free, also i have added products in wordpress but when i select the store url it shows the word products but when selected it just shows a blank page. if i select category then it shows the category and packages, just now when i select products. problem something that i have overlooked.