Cheapest option would possibly be to source a used complete copy from bricklink or eBay (Australian sellers have these for $350 currently) and then sell on the parts/minifigures you do already have. Stickers can be picked up from bricklink or you may be able to get them printed in the aftermarket.After working with me for a week to try and identify what I'm missing from the Friends Apartments, I think we understand what I need... and Lego have decided they aren't going to help me.
I'm shattered, I'm missing the stickers - which they say they can't replace, and I would've lived with - and 2 whole bags of pieces. Now I need to decide whether I can be bothered going through the instructions to identify and order every piece from those 2 bags (and order stickers off Bricklink), or whether to stop throwing good money after bad, see whether I can part it out, and just try and recoup the loss
Given every experience I've ever had with Lego, I was stunned that they've decided not to help me. Even moreso when the implication throughout this week is that they were going to help
Of those 2 options, I think identifying the missing pieces is probably easier, but who knows? If there are minifigs or anything particular in the missing bags, it becomes a whole ****around of pick-a-brick orders and ordering individual parts off Bricklink, which could get insanely expensive.
Yeah you can identify the missing pieces and order, but by the time you've gone through all that it probably makes it much of a muchness financially, particularly if there are rare parts in the missing bags.