Nvidia 8700m gt slave vs master

The video card in my M9750 finally went kaput, just shows a black screen but if I let it sit and type my password i can hear windows log in. Like the title says, its an Nvidia 8700m gt, the shop i took it too said it would be minimum $400 just to buy the replacement card, but I've found several on eBay for around $100. Problem is, they're all listed as SLAVE GPUs. I only run one GPU, so does it matter if I use a slave gpu vs a parent one? Some sites I've checked say there no difference between a slave and master gpu, others said they have different heat sinks and connectors and wouldn't even fit in my laptop. Anyone know if the $100 ones would work or will I have to shell out 4 - 5 times that like the shop said? I'm living in australia at the moment so it will be about $40-50 just to ship it down here, and if I have to return it I still have the pay the shipping on the way back so buying one that doesn't work would be a colossal waste of time and money. Any help would be appreciated.