1. Create a "Business" account with PayPal (www.paypal.com), it is free to create this type of account. The fees for this
account applies to payment transactions only.

2. Sign in to your PayPal account and create a donate button with a name and an id. Get the code for the donate button which
will include a command value and a button id.

3. The code that you get will look something like this and this code will not work in a ASP.NET form:
<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_s-xclick">
<input type="hidden" name="hosted_button_id" value="QWEQWEQWEQWE45">
<input type="image" src="https://www.paypal.com/en_US/i/btn/btn_donate_SM.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
<img alt="" border="0" src="https://www.paypal.com/sv_SE/i/scr/pixel.gif" width="1" height="1">
</form>

4. The code that you will add to your .aspx form should look like this to work on a ASP.NET form...:
<a href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=QWEQWEQWEQWE45" target="_blank">
<img style="border-width: 0px" src="https://www.paypal.com/en_US/i/btn/btn_donate_SM.gif" alt="PayPal - The safer, easier way to pay online!" /></a>

... which means that you have to create a link with parameters. For the "cmd" parameter you set "_s-xclick" as the value and for the
"hosted_button_id" paramter you set the value for "hosted_button_id" as the parameter which in this case is "QWEQWEQWEQWE45".

5. A link with parameters will redirect the user to a PayPal form were they can donate money to your PayPal account from there credit (debet) card
without having to create a PayPal account for themselves.