You will want a ring as an expression of your commitment. Go down any high street and you can pick a price double it multiply it and then double it again.
There are two things that are not requirements. A wedding ring does not have to be gold and it does not have to be new.
You can look in car boot sales, flea markets and second hand shops for a ring and you can find something that is amazing value.
Ask some older members of your family. There may be a family ring from an aunt or great grandparent that has been saved for a day like yours. Most people agree that a special family ring carries more significance than even the highest priced new ring.
I'm told by one couple that they saved their Tesco Clubcard points and used them to buy their wedding rings.