Scandoubler/flicker fixer is integrated in motherboard on A3000. You can use any Zorro graphics card, preferably a Zorro 3 card with a integrated video switcher.
Here in Sweden basic stock A3000 sells for 150 euro. You can get 060 card for A1200 for about 150-200 euro, dont know if A1200 is so expensive.
Cheapest is A2000, nobody wants them. Finding a turbo board for them is tough though and they are slow as hell with Z2 graphics in hi-resolution.