Yes. Mail-in rebates are common in the USA (thankfully not as common as they used to be). USA rebates are normally restricted to customers that reside in the USA. This means that you will miss out on most USA rebate if you order directly from a online USA shop. Because my USA partners order from stores as an individual's they are able to process these USA only rebates.
The major problem with mail-in rebates, apart from all the extra work involved in filling them in, is the payments typically take 6 to 24 weeks to be returned. For this reason I recommend not choosing items with mail-in rebates unless the rebate is substantial, especially if you can get the item for a couple of dollars more elsewhere without a rebate.
If your order does have a USA mail-in rebate the normal process is you pay the full price (ie the price without the rebate included). When the order arrives at your address you may need to remove the UPC from the box (nearly all mail in rebates need this UPC code) and send it to my USA partner. When the rebate payment arrives you will be refunded the rebate amount minus US$10 to cover my USA partner's expenses. The reason they don't refund 100% of the rebate is there is typically a lot of paperwork involved in processing mail-in rebates (any minor mistakes can cause the rebate to be rejected). The US$10 cost is charged by my partners to cover the extra work involved.
One thing to keep in mind if you are wanting to take advantage of a rebate is the conditions of the rebate. Most rebates must be submitted either by a fixed date, or within a certain number of days of purchase. Because of this it is critical that you check the rebate conditions before ordering. My US partners will make every effort to obtain the rebate, but sometimes it just is never issued by the processor.
If you want to take advantage of a non-cash rebate then please contact me. The cost of processing these rebates is US$10 plus any associated shipping charges.