Policies vary. Contact the store(s) directly for an exact answer. In general when that much cash IS accepted, a cash REFUND (if you return the item within 14 days) is NOT available, required as a deterrent to money-laundering. Any refund would be by check within a few days.
For most MacBook Pro models, the exact model you want will NOT be in stock, so an order is required. Obviously, a cash transaction for an online order is impossible, but a Bank transfer is an option from a bank in the same country as purchase.
You can also order in-store and pay on order. I find I cannot concentrate adequately and check and re-check the details properly when ordering in person at the crazy-busy store, so I PREFER online ordering.