A good brand for a home security system would be GE, They are a top leading brand that offers good security benefits and safety from other leading security providers.
ADT and other home security and monitoring companies will often offer free or discounted alarm systems if you sign up for a year of monitoring. I would check to see what their current specials are...
"There are several great options for home audio system speakers. There is a difference however, depending on how you want to use them. For listening to music Bose, Yamaha, and Sonos are highly rated."
The price of home alarm systems depends on the brand and complexity of your system. Some systems just contain alarms if doors or window are opened, while others contain cameras.
Home Security systems will differ a lot dependent on your needs, some will include camera monitoring, others alarms with phone calls etc. A good system will depend on what you want to pay for it and...