Wal-mart has some cute patterns at a reasonable price. Also if you have a Salvation Army nearby, they usually have scrubs for $1-2 per item. Sometimes you can find cute patterns there, but often times they just have solid colors. If you bought a cute top at a retail store, you could pair it with the inexpensive bottoms at Salvation Army.
Where I live we have some local scrub stores that offer discounts to students and health-care professionals. One local store where I shop gave me 10% off each time I shopped and I was on their mailing list so I would often get 25% coupons. Call your local stores or stop in and see if they have any discounts or specials.