Last time I checked the price for Schiphol it would be about 200 euros, including handling. Bose-X may have gotten a better deal but I decided not to pursue it any further.
Nearest GA field is Hilversum. It's a grass field with three runways, surrounded by trees. It is wedged between the Schiphol and Soesterberg CTRs with not much room for navigation errors. Make sure you prepare your arrival thorougly.
Another field you could use is Lelystad. One large bit of tarmac, pretty busy but very easy to approach - make sure you adhere to the VRP Bravo though, and contact Lelystad at least two minutes before Bravo. There was a nasty midair last year which killed two members of my club, and they have really tightened up their circuit procedures, radio procedures and so forth because of that accident.
Geographically, Hilversum is closer to Amsterdam but public-transport-wise, Lelystad is probably easier.
Oh, and Lelystad is comparatively pricey for an uncontrolled GA field.