In principal your purchases will be set from the UK and most stamps are send in carton birthday cards which will not attract customs attention. A big advantage of Royal Mail is that you're compensated up to £ 20 in case of loss. I  travel to the Netherlands and Belgium several times per year and can ship your purchases at local tariffs if you're willing to wait. The savings can be considerable for shipment up to  20 gramms but  there's no compensation in case of loss! 
 
Prices will be converted from £ to € at the rate of the day - the tariffs below are only a basic indication for the most common shipments - for more info see Royal Mail or ask me for calculation of shipping tariff applicable for your country. 
 
 
UK standard letter 100 grams - 1st class £ 1.75  2nd class £ 0.93
 large letter  100 grams - 1st class  £ 3.25 2nd class £ 1.65
 large letter  250 grams - 1st class  £ 3.70 2nd class £ 2.10
Europe
standard letter 100 grams £ 3.45
large letter       100 grams £ 3.65
                        250 grams £ 5.95
World
standard letter  100 grams £ 3.45
large letter        100 grams from  £ 4.45
                         250 grams from  £ 7.85     the ‘from’ prices depend on your World Zone 1, 2 or 3 so message me for the actual shipping price. Most countries are in World Zone 1 (the                                                                          ‘from’ price) but not  USA and Australia/New Zealand                                    
Upon request, I will always look at cheaper alternatives for shipping if they exist.