If it's a product that's getting installed, then something like this:
(say it's a free radio install)
'we also offer free installation on this radio (normally a $35 charge). We also offer extended service plans that can cover your radio for up to 4 years.'
Then, later when you ask for the sale,
Explain the extended service plan. NEVER use the word warranty. Call it a service plan, or protection plan. I don't know if you have the CA kits, but those come in handy- they come with coupons for $10 off install. If I'm selling a DSR with install, I can get service 95% of the time- say it's the Starmate- 2 year plan is $12.99, and take $10 off install, they only pay $3 for 2 years of service...who would turn that down?