Costa Rican customs duties

I have a small flat screen tv,laptop and small printer.Will these require import taxes?

If you are bringing them with you (e.g. on the plane), then you shouldn't have any problem.  Certainly not with the laptop. If the other items are for business use, then also no problem.
We've brought in similar items, and never had a customs stop.
If customs does say that you owe a tax, then just use your exemption - each person gets $500 worth every 6 months; they just put a stamp in your passport.  Note: if you're traveling with another person, make sure to just give one passport - you don't want both stamped unnecessarily.