No doubt, new windsurfing gear can be an expensive investment. What I've found is that time and patience can be your friend. Each year, I try to target important investments that I need to consider. Over time, you can build an awesome quiver of stuff that doesn't break the bank all at once. Another thing that helps greatly is to keep the stuff you do buy for a long time, and avoid the strong temptation to keep up with the latest fashion.
Lastly, although it doesn't fit with everyone's way of doing things, there's always the credit card or line of credit method of buying things. While one does pay an interest penalty to buy on credit, it does allow one to spread out the payments over time. I bought my first complete windsurfing kit, to include racks, by refinancing my car. Overall, despite the added cost, I never regreted that decision, not for one second.