美味しそう
Both sentences are ok. I think that I would probably switch them around and say:
Eating at a restaurant is very cheap.
To eat at a restaurant is very cheap.
I would also change the word 'cheap' to 'inexpensive' or 'reasonable'. In the UK, cheap usually means a low price for something that is lower in quality. We have an idiom that expresses this: 'Well, you get what you pay for'. Inexpensive or reasonable sounds more like you received something of good value even though it didn't cost a lot. 😊