Please get some Frontline. If you are going to own dogs, that is part of responsible pet-parenting. Ticks can transmit many diseases and can kill your dogs or cause them neurological damage.

I wont even start about fleas.
Ticks can transmit very serious illnesses.

And if you are *concerned* about the money, (1) you might only have to apply it part of the year depending where you live and (2) think of the money you will be out when you have to take your dog for neurological testing after a tick bite.