Well it all really depends on the exchange rate and the product. Also the second hand values of products are totally different in Poland than in the UK or in Germany.
Right now its about 5.3/1 so it is less profitable to look at products in the UK. A month or two ago the exchange rate was close to 4.8 which was a great time to buy in the UK. Now, a pair of grills costs 319PLN (60GBP) in the stores new. An Ego9 costs 4300PLN (811GBP) in the stores. This exchange rate makes some products seem very cheap. With regards to used items, they are a lot more expensive here than in the UK. Probably because the community is much smaller and there isnt as many second hand products for sale here so people can demand a bit more.
You definately wouldnt find some great deals like you do on p8ntballer. I cant even dream of trying to find grills for 25 or 09 distortion pants for 60-75 in poland ;D. If I didnt have my markers then I would also buy them on these forums. Shipping the big stuff (kit bags etc) is mostly not profitable as I just found out.