For the past few years, I've used Google Spreadsheets when I wanted to create a small database quickly. Database concepts can be implemented using spreadsheet formulas. Each spreadsheet tab represents a database table; Joins and queries use VLOOKUP (or MATCH/INDEX to optimize); GROUP BY queries are either pivot tables or other formulas. As VLOOKUP count increases, performance goes down, but it's worked reasonably well and Google Spreadsheets is free!
However, there are a few issues: