I find it expensive with RoyalFail or ParcelFarce, along side a poor service with silly pricing if you want tracking or signed for delivery confirmation.
I think it was about £12-15 for one AES game well packaged with signed for delivery last time I sold an AES game.
If you're posting more than 5 games then it'll cost you a fortune, so you might as well go for DHL delivery via
www.parcel2go.com for £17.99 + VAT, 4-5 day delivery with tracking, you don't get that elsewhere included without paying out the ass.
I recommend packing well with any method as well, don't think because the service seems high quality for its price, they still play football with packages.