We will use two vilionists in the ceremony and play chinese traditional music CDs in the reception. I never thought about using a DJ, so I don't know how much it will cost and what DJ does in a wedding.
If you like live music, there are many choices,. you can do solo, duet, or trio on many music instruments, such as violin, piano, cello, guitar, etc. The costs should be cheaper than a band, (I guess).