Besides having to include the cost of a Windows license, the cost of the MSSQL DB needs to be added as well. I doubt you'll find something that performs well in your current budget, but there may be some offer somewhere.
High Bandwidth Servers
Custom Hosting Solutions
With SQL Server Express edition - you will be able to have a database with max size of 4GB whereas there is no limitation of database size with SQL Server Web edition (unlimited database size). Hence, you will just need to ensure that you have enough amount of disk space on your VPS and your db size will be able to expand till that...
██ Softsys Hosting ██ - 8 Years In Business - 24/7 In-House Support - Enterprise DDoS Protection Available!