Basic Magento Install w/ Custom Payment Amount Per Product

Rainmaker Fundraising is a non-profit organization whose primary goal is to lead reconstruction efforts in Haiti. The website is rainmakerfundraising [dot] org . We'd like to add a simple donation platform to the website where users can donate to the the project in general, or to a particular part of it. We'd like to treat this interface as an ecommerce platform, where the particular parts of the project (and the general project as a whole) are considered products. See the attached wireframes for what we're looking for. We'd like to use the same general style and header that is currently on the site, and then on the main page of the ecommerce platform (which will live within a directory /donations), we'd have 3 different components: 1) Prominent link that takes person to product page for "General Project" - basically, we'll treat donations to the project as a whole as 1 product. 2) Beneath that, there will be a box containing the rest of the products, with an image of the product and the product name. To start, there will only be 4 products in this area, but this area should be able to easily handle more in the future. This should be done by using a "Featured" category and having the home page pull products from that category. No paging is necessary for now. 3) In the right sidebar area should be the shopping cart which lists the amount of money donated to each product. The product page should be pretty straightforward with main box for product details and the sidebar widget to the right. However, the key difference from normal Magento product pages is that we need the ability to allow custom price amounts for the product. So the user can either choose a particular price in intervals that they can set up in admin panel on a per product basis ($10, $20, $30), or indicate their own price, and then add the product (with the specified price) to the shopping cart. From the shopping cart page (typical Magento shopping cart layout), users are redirected straight through to a standard paypal account to finish the donation. So, all in all, this is a really straightforward Magento ecommerce site, except for the custom price options for products. We have a very well scoped out project, and a lot of technical experience to communicate about the web development work, so this should be a pretty straightforward project for someone to take on.