If your going ROP (Run of Paper) you can probably ring in on deadline and say what you are prepared to offer with newspaper advertising you need to have a small advert and consistency. So classified would be the best, sure you can negotiate a price. Rule of thumb for copy writing is the following, hope it helps. If your going to do it OP go for classified and ask what they can do dont do ROP.
Sure they will be open to negotiate a price.
A small 5 X 1 col will suit
A attention
I interest
D desire
C conviction
A action line.