Cheap video surveillance?

I have a home office. I do property management and maintenance for 120 apartments. I collect rent as well and have rent drop slot in my house. I would like to do a video surveillance system since I can have at times decent amount of money in my rent drop slot. We are talking few thousand here...

I was looking at the video surveillance systems at Walmart and Sams Club. The best one with DVR and four cameras runs around $900, the least expensive one is $250-$300.

I was thinking of getting a wireless web cam and running surveillance through my computer. All I need is web cam pointed on my drop slot which is next to my front door and one web cam pointed on the inside of my office.

Anyone has any experience with such system? Any advice would be appreciated.

 

For around $160, you can get video and sound with a baby monitor. I'm not kidding. It is wireless, and sees in the dark. you can hook the part with the screen to a dvd recorder or a computer with the audio/video wire it comes with.