Thanks a lot for your reply
By the way ,Tto save the space, I want to have slot on the pcb, does pcbway support it?

Yeah! Definitely! I think it is a regular technology. But you can confirm by contacting them. Email is available here: stacey@pcbway.com

 

I've been using http://www.shenzhen2u.com/

You should try it. The price was 11,90$ for 10x10cm boards ( 10 pieces)
There are many shipping options, and the prices of them are also OK.
+ they send you a picture of finished boards when they make them

Here are my boards. Double sided, silkscreen on both sides, and I've build my stuff on almost all of them and they all worked.