Museums are always a classy idea, even when it's FREE!
If you've enjoyed The Getty Center in Los Angeles (see Cheap Date Idea #32), then you have to check out The Getty Villa in Pacific Palisades, near Malibu. Of if you simply appreciate architecture and gardens, then this spot is for you. The art is interesting, but I personally love just strolling around the estate weaving in and out of the fancy statues and fountains. The weather was perfect when we went as you can tell by the photo here.
The Getty Villa is a great day date idea anytime throughout the year (including Valentine's Day, hint hint) since the museum is open daily 10 AM - 5 PM except Tuesdays. Admission is always free but reservations are required by internet or phone (click ). It's also a good group date idea, but you have to call in for your reservation if more than 15 people. Parking is not cheap ($15), so carpool if you can or take the Metro.
Just like The Getty Center, various free tours are provided at the Getty Villa, so check the schedule online to plan your visit accordingly. I recommend going on the Architecture and Gardens Tour, but you can easily wander about on your own if you prefer. During the month of February at 11:30 AM - 1:30 PM (including Valentine's Day), The Villa is offering free Glass-Handling Sessions if glassmaking peaks your interest.
While you are up in this part of town, make it a full day of fun and stop by Lake Shrine for free too (Cheap Date Idea #38).
Approximate cost of creative date idea = FREE + $15 Parking.
Actual value of the cheap date idea = Priceless.