Here's how you do it:
1. Login to paypal under the “merchant account“ you set up to accept payments. I'm not sure if this can be done without one...
2. Go to the “Merchant Tools“ tab.
3. Click “Buy Now Buttons,“ tucked away in the first paragraph that has the title “Use PayPal on your website!“
4. Enter the details in the form. For item name/service, use something like “Site Donation,“ and give any number for the item id/number. Have whatever price you like, select the currency...
5. Select the “Buy Now“ button or provide one of your own.
6. Under Security Settings, click “No“ to encrypt the payment button. Normally, it'd be a very bad idea to do this, but since you're accepting donations from your members and not actually charging for a service, it shouldn't be a big deal.
7. Click “Create Button Now“ to complete the form.
8. Two text boxes with code in them will appear. The code you want to grab is the code in the “Link for Emails“ text box. It contains everything necessary to send the user to PayPal to donate to ya. Here's a sample of what these links look like (please don't donate, lol -- this is just a sample!):https://www.paypal.com/xclick/business=Support%40guildportal.com&item_name=Site+Donation&item_number=1111&amount=1.00&no_note=1¤cy_code=USD