Of course it varies but there is an average price for an area of agricultural land and it is this I am trying to find. As I said two years ago it was 1500 euros. I am trying to find if this has changed much in the last few years.  For making an offer on land go to the ajuntamineto and find the parcela and poligono numbers and they will tell you who owns it and their address. Go and make an offer.
Bruixot