This will primarily depend on whether the wall is weight bearing or not. You might also have to add or modify some foundation supports.
Seek the advice of a licensed General contractor in your area.
1. Are you going to pull permits?
2. Is the wall load bearing or not?
If you're only going to cut an opening, even if the wall is load bearing it shouldn't be a big deal, they just put a header in. Shouldn't cost more than a few $K finished.
That said, if you want to keep costs down and get more light and open feeling the best way is to cut an opening like a window because all you need do is add an extra stud and a header, but keep in mind it could get expensive if you do with permits because they'll likely want an engineer involved.. If you want a real estimate, contact some local contractors - local agents should be able to give you referrals - and get some real world bids.
You might also open a hole in the sheet rock from one side so the contractors can see what's going on underneath.
Lance King/Owner-Managing Broker
King Realty Group
Is their electrical in the wall that needs to be moved?
Is their plumbing in the wall that needs to be moved?
Is the wall a low bearing wall or not?
Based on this only a contractor can give you an estimate.
Have a great day;
CEO & SR Credit & Mortgage Consultant of
Ex-Mortgage Broker of more than 10 years
You would always have to install a header no matter what and as Steve pointed out if it's a load bearing wall you may have to reinforce under with a couple of piers to counter act the point loads on both sides of the opening if it's a raised floor as it would interrupt the uniform displacement of the continual load.
If it's a slab on grade you could run the risk of cracking the slab if it's a load bearing wall so further engineering may be needed to calc out the structural dynamics. I've seen too many folks try to piece meal improvements through to save a buck or two only to have it end up costing so much more in the long run. Hope this helps.