I don't think it would be too difficult.
On the wishing well page (http://www.neopets.com/wishing.phtml), is there any way to make a script which would automatically fill in the "Amount of Donation" space with '21' (the minimum donation needed to receive a price) and fill in the "What item do you wish for?" space with an object of your choosing (meaning something that you could insert/edit in the script itself).
I'm not sure if it actually is difficult or not, but if someone could make this script for me, I would be forever grateful!