I see this all the time in forums I read.... lawnsite and thegrimescene.
Someone sees an ad in the paper or craigslist and cannot believe what prices are listed. I have to admit that my jaw drops sometimes when I see crazy pricing. Most of the time it is people just doing a bait and switch or just up selling a higher priced service. Or it is possibly some nut who hasn't a clue how to price hi / her work or they are just in a slow season and have free time that needs filling. Whatever the reason , you cannot get caught up in what the other guy is doing. Do quality work and find quality clients, who are appreciative of consistent service providers and you will not have to worry about low ballers. If you do find it necessary to compete with price cutters, be ready to deal with people who will not be ideal clients. They will usually be ready to drop you as soon as a better deal comes around, they will want an as "needed" service (not a consistent schedule), and they will expect freebies because they do not value your work.