1996 Other Saturn Models Engine noise, but no warning lights

I recently purchased a 96 Saturn SC2 coupe for a daily commuter and have a little fun with. I paid $1400 dollars and drove it about 300 miles in the first 5 days. Went and got the oil changed and A/C charged. Everything seemed fine then I began hearing a small tapping sound coming from the engine and it would increase as I increased the RPM. No warning lights have gone off and I had the oil checked again and nothing was seen. I took it to the shop and the mechanic doent think it is a stuck lifter, but rather it is coming from the lower end. What other signs and symptoms should I look for to be sure he is not trying to take me to the cleaners. Is the car even worth getting fixed if it needs a lower end repair? Just need some advice before I put any more money into it.