Php shopping cart fix

I have a shopping cart which have a type of product with quantity, size and length. Now when i change the quantity to 3 for a product, it should ask me to choose 3 lengths and 3 sizes and also save it in the session. Also this should work for multiple products. I already have the full shopping cart. I want an excellent PHP developer to do this job and i have a fixed budget of 30$ for this job. This is a less than hour job for an such developer. Please be sure that you can do this, no payments before job completion.