Weem, I'd love to hear the specifics on how you do this. Do you have a document with the cards that you can share? Details, man! Details!
I lub me some FATE.
Someone somewhere (I don't think here at ENW, but I could be wrong) had a system drawn up of ways to spend the fate points in 4e. We tweaked them a bit, and a friend put them on a card he made - then he set up a 3x3 sheet of them to print and cut - I just asked him about it but it's at home otherwise i would post it.
Anyway, some of the options for using one include getting a +3 to attack for your daily, +2 to attack an encounter, +1 anything else (all AFTER having rolled). There were a few more things on there (not coming to mind atm)... maybe a re-roll... and possibly an extra action. To hideout was ever discussed before that, I just kind of wanted one all of a sudden... he could have denied me, but he also may have then given me another one. If you know the Aspect/Fate system you already have an idea of how it works, etc.
But, what it primarily get's used for is to do something cool - we kind of explain what we want to do in exchange for the fate point - DM decides whether or not to, or modifies the idea, "well, sure, but just this part of it... and you have to roll an Athletics check to land without falling prone" etc. As a DM I will accept one to auto-succeed just about any skill roll, and I am willing to break rules for cool effects. When players get excited about doing something cool and are willing to spend one, I'm pretty much down for whatever.
In my game, you get one 1 per session. They don't last to the next session if used, and you can get an additional 1 during the game for cool RP-ing or ideas, etc.
---edit---
As a player, I make sure I use one each game.
EX: We busted out of an Inn we rescued someone from. I play a goblin rogue, and knew the city best. We didn't know where to go, so I offered up the DM my fate point card and said, "I know JUST the place to hide! My little hideout!"... DM smiled and said, "yes you do" taking the card. I didn't have a hideout before that, it was never discussed - and he could have said, "no, that was in the other city" etc, but he also may have given me another FP for the idea then. I'm sure you understand that part of the system though (the bartering) - much fun
