If you are having a wishing well at your wedding, many brides include a wishing well card with their invitation, to let their guests know that they can give a gift of money.  Something Fabulous has  pre printed wishing well cards available on line with a lovely verse that can be easily slotted in with your invitations. Follow this link  http://www.somethingfabulous.com.au/categories.asp?cID=71 

We have also found a verse that you might like to use if you want to let your guests know that if they prefer to purchase a gift it is fine as well.

If you were thinking of giving a gift to help us on our way
A gift of cash towards our new life would really make our day
However, if you prefer to purchase a gift
feel free to surprise us in your own way

Hope this helps

Lynn