Garmin ( GRMN) was a top destination in the GPS device boom, but navigating the post-boom is proving to be a challenge. The numbers. While rivals like Magellan and TomTom have typically offered the cheaper options in GPS, Garmin is going on the offensive this Friday. For the first time in a national retail offering, Garmin will break the $100 barrier with a $99 device. The Garmin Nuvi 205W is being advertised for $99 at Best Buy ( BBY) this Friday, a 29% discount from the $140 regular price. The stock. Garmin shares are down 16% in the past month as analysts and investors absorb the shock of weaker margins on new devices like the Nuvi phone. Deeper discounts, it seems, aren't exactly the right road toward alleviating those concerns.