Save your money for the summer sale.
Valve has been doing these small minor sales and while they may seem nice like 20% off the game you want if you wait for the summer sale that game you want will be 90% off.
See Valve knows they can bait people into buying games for a discount, what people don't know is that they sell the game even cheaper the next day to piss people off and then it's too late for the people who paid more than they should have.
I've seen the Tomb Raider classics on sale for like $1.25 and the next day they were on sale for .40 cents and everyone was mad they lowered the price so randomly after just buying the less discounted version.