The Donation Goals module lets you create nodes of the type "Donation Goal." These goals allow you to set an amount of money you'll need for whatever you're saving up for. Visitors of the site can then donate money through PayPal. Once the target amount is reached, the donation form is hidden. If you're putting in some money yourself, you can easily just update the amount you've saved without having to donate through PayPal yourself - saving you any fees.
Using permissions it's also possible to deny donations from users. This may be useful if you don't accept donations, but just want to show how well you're saving up to get that big thing from your wishlist. Or you can make sure only authenticated users make a donation.
For detailed usage and installation instructions, please read the README.txt file.