My ADT rate has crept up from $25 to $41/month. I was considering changing over to Simplisafe and called ADT to whine about their rates. If you don't bite at their first few offers, they'll reduce you to $15.99/mo for 6 months and $29.99/mo from then on without signing a new contract. If you want to do a 2 year contract, they'll do $24.99/mo. I opted for the no new contract and in 6 months will probably just call them back and see if it's time to switch to Simplisafe or not. Not life changing money, but worth a 5 minute phone call.
Note they offered $34.99/mo at first. Then $29.99 with a 5 year contract (lulz, no). Then $24.99 with a 5 year contract (lulz, still no). Then $24.99 with a 2 year contract. Then the 6 month promotion and $29.99 with no contract.