plasterboard access points

[smooth_exteriors]

do any of you guys use plasterboard access points. the picture frame ones im looking for 600x600 and 300x600.
where is it best to get theses from and what sort of money do they go for. ive seen them online in excess of 100 quid. all help appreciated

 

[S a plastering]

try www.buildingmaterials.co.uk there is one on there for about 55notes mate