Well my way to approach this, in the case of buying an Audi S4 which has a full plastic underside cover, was to buy a set of 4 Jackpoint Jackstands.
A cheaper way, in the case of Polo/
Ibiza/Fabia, if you normally use trolley jack, is to buy and fit a set of 4 Audi TT jacking point protectors and fit them in to the correct holes in the underside, then use the folded strengthened sill areas to locate the axle stands though it would be smarter to modify the axle stands to suit the sill lifting areas.