Just had to write this as I recently brought a sequinned Union Jack handbag from Accessorise. This is a gorgeous bag which is sold at £30.00 through out Accessorise stores & online. I have since noticed them for sale on ebay at 50% more than you can buy them in store! Then you've got your P&P ontop.
Also there are other Union Jack bags which are advertised as being sold out in stores (not sure of prices on these) so far Ive seen this apply to River Island & Julian McDonald at Debenhams - dont beleive it as I've seen them both in my local stores in the last weekend.
If you really love it & cant get into a big store then fine but Id advise you do your research first & dont pay over the RRP.