Balancing Values

I guess it depends on what you are trying to balance. For example in a 2 to 4 player game using 100 cards and having a hand size of 5 you are going to a minimum of 10 to 20 percent of the deck in play at any given time. Now how often do you want card X to come out. If there is only one card X in the deck then you still have a real good chance that it will be out in the starting hands.
All analysis aside set down by yourself and play through a game making the best effort to play as if you don’t know what each player is doing. This way you’ll find little flaws that you can fix before going to real players. One thing I sometimes do is assign players types like the reserved player who will only go for a sure thing or the novice player who will make plays that are almost random. I think this helps me decide what each player will do on their turn.

Great question. One suggestion I had from one of my playtesters is that it's not always a bad thing, in the early stages, to have a game that is deliberately unbalanced. It can be very hard sometimes to separate effects of minor imbalances from effects of sloppy play. But, if you make little attempt to balance things, it should be more clear how you'll need to tweak the game to get it to be more fair. Of course, this requires very patient playtesters, but you could solo playtest as well.

Another thing I would suggest is that you not just think about cost, but about timetables and practical utility. For example, in one game I designed, there was a building that you could purchase for $10, which by the game's standards was expensive. Now, the building's function was powerful enough that the cost was a fair price, however, because it was expensive, people couldn't afford the building till late in the game, but the building's function was more suited to the early game. The point is, you don't want to just think in terms of setting a fair price, but also making sure that the cost of the ability/building/upgrade can be afforded at the point in the game where the ability is most useful. If not, scaling back the ability (and also the cost) might help. The best example of this, of course, is Puerto Rico, where the "big buildings" are well suited to the mid-to-endgame, which is also the time when players have enough cash flow to afford them.

Good luck with your project!

-Jeff