Welcome to this place, and very much welcome to Belgium! Myself am based at EBZH Kiewit, right in the heart of Belgian Limburg. It will be my pleasure to offer any assistance you might require.
Could you please indicate (more or less) what type of plane you will be flying, and whether VFR or IFR? What are your planned aerodromes of departure and destination?
Just to give a bit of indication: my homefield EBZH, and also nearby EBKH Keiheuvel, charge 5 € landing fee; both have a pump for AvGas, but MoGas would require prior arrangement. Both have an excellent bar/tavern/restaurant, too. A major field like EBAW Antwerp still has quite reasonable charges - some 40-50 €, ISTR - with again a fine resto available, and fuel, and what not.
If you fly VFR, and below 2000 kg MTOW, I understand no direct cost will be levied except the aerodrome landing fees.
A major warning about the Limburg area: Kleine Brogel EBBL is an active fighter base, mind your P's and Q's round there. They may even go at Quick Reaction Alert for a scramble of interceptors in which case their airspace will be closed to all and sundry.
And before I forget, 8,33 radio and mode S transponder are almost mandatory - 8,33 is absolutely required, mode S can still be avoided by flying outside controlled airspace - which means below 4500', and carefully avoid the many CTR's and TMA's - and strictly VFR.