If a seller has a lot of 99c auctions I avoid them. If the seller thinks that is all the items are worth then they must be in pretty poor condition.

It can be useful if you are listing free and you have one 99c start just to get people looking but you must be prepared for it to sell at 99c.

I list n item once and if it doesn't sell I either relist on my store id as a BIN or I leave it a while and list it with a higher start price and more often than not it sells.