Broken screen, where to buy replacement parts

Hello everyone,

My girlfriend broke her iPhone 4 screen recently and I decided I want to repair it myself.

I have done screen replacements before but the main problem is where to get decent quality parts.

The cheepers ebay screens which are between $18 and $20 wrok just fine, however they are not very high quality.

There are sellers which sell $40 screens but I am wonderen whether or not these will be of better quality.

Can anyone recommend a certain ebay sellers or does anyone know a good place to buy replacement parts?

I live in the Netherlands so US webshops won't be the best solution I guess.

Thanks a lot:)