If you aren't suited - try joining the Cruising Association (they have a stand at the Boat Show!) They run a good chart exchange. I have bought Admiralty charts corrected to -1 year for £5 each for our cruises which have been 2000 Chichester - St Petersburg - Chichester, 2001 Chichester - La Rochelle, 2002 La Rochelle - Torrevieja (Costas Blanca)
Once overseas, there appear to be fewer inhibitions over copyright & so on than in the UK.
Photocopying charts is a good excuse for socialising with fellow cruisers and costs a few £ per sheet.
I too have used Marine Chart Services. If you can think ahead they will keep a 'wish list' running and put charts by for you as and when they come in and charge them to your credit card. It works well.