We use a uniden guardian system from costco. Can remote view, records to SD cards. Easy to use, uses up to 4 wireless cameras. System came with 2 old school security style cameras for 300, we added 2 smaller baby looking cameras at ~75/each. You can hear sound on the monitor but it doesn't record with sound. The baby style cameras have batteries, so you can move them without the stand and power for short periods of time.
Video isn't as clear as a higher end security system, but good enough. Night vision is good. Easy to pair (literally just press a button). Can record on a schedule or on motion.