There are several ways that you can reduce the cost of drafting a contract in respect of third party reproductive matters.
1. Find a family lawyer that practices some third party reproductive law. Despite what the third party reproductive lawyers will tell you, this area is not complicated or difficult for lawyers to navigate (I am assuming you are in Canada) and a good family lawyer will be able to do it. Family lawyers are likely less expensive and may also be more flexible about you doing the drafting (see below) and having them review the document, as they usually have LOTS of clients already.
2. Find a (local) friend who has recently had a lawyer prepare an egg donor (or whatever) contract. Change the terms as you need them changed. Have your lawyer review. The lawyers all use the same contract forms, and most of the contract is the same from client to client. It's important that you don't cut out the step that you have your lawyer review. Don't get a contract from the internet as they vary considerably jurisdiction to jurisdiction.
3. Find a lawyer for the donor (or other third party) who is easy to work with/ doesn't force or invent issues. Ask your lawyer for someone they feel will be agreeable.
4. It is very important that both sides are represented by lawyers. Don't cut costs by cutting out the lawyers entirely. Again, I am assuming you are in Canada.
5. Scrutinize bills closely. Look at what your lawyer was doing (you should have descriptions for every minute worked) and push back if it seems unreasonable. Note that back and forth with the other side can eat up a lot of time so hence item 3. There is a mechanism to dispute bills with the law society.