If you're after cost-effective astro filters, many quality brands to choose from. I found this site has the best prices. They don't ship scopes internationally but most small components are really good value and available to most international destinations. They also accept paypal.
I must be honest though, they did muff up an order I made ages ago but were very quick to send the correct part out and they covered postage. Service is quite good and postage can also be very good value. They have different post methods to choose from. They are also on eBay.
www.agenaastro.com
P.S. I meant to infer that most filters not all are best price on the internet. Most GSO stuff is cheaper here in Oz at Andrews.