Customizations to my wordpress site

I have a website I'm creating that deals with Tattoo Artists and people looking to get Tattoos I want it to work like this. For example, if you want a new counter-top installed then you come to my site and post your project. Contractors bid on your project (similar to Freelancer.com) and then the customer clicks the "choose winner" button which then redirects them to Paypal to pay a 10% initial deposit in order to set up appointment. I understand that we can redirect customers to pay a set amount, but is it possible to charge them a certain percentage of the total instead? Can you please help because I'm really stuck with this one, can you accomplish this? my site is [login to view URL] I also need to make some pages more attractive and also show avatars next to usernames in bdding panel and provider search here i need to make provider search look similar to freelancer.com freelancer search,show avatars next to username etc. ok on the job bidding page i need bidding usernames to show and want it similar to freelancer.com layout [login to view URL] my site is based on wordpress let me know if you can help ONLY EXPERIENCED FREELANCERS APPLY! I HAVE HIRED PEOPLE ON HERE AND THEY CANNOT DELIVER. I KNOW WHAT I NEED