You'll pay to have the tree removed. People aren't falling all over themselves to get walnut.

Save the tree, please.

Well, some people are. You might look around for a woodworker's group or Trees to Furniture. There are probably some people who would love to have the logs - if it's big enough, i.e. at least 18" diameter at chest height.

However they may not be equipped to take it down, especially if it's close to your house. Still may require a tree removal service. Even so, if you can find someone who wants the logs, you might make a deal with the tree service to take it down, cut it into the proper lengths and leave the whole thing, at a reduced rate. The logger removes the whole tree in exchange for the logs. I did that once with a 30" walnut, owner paid to take it down, I removed every stick. We were both happy.