When you setup a new sensor, it is likely that you will choose to utilize either a SPAN (mirrored) port or a network tap in order to get to get packets to the collection interface of the sensor. Most enterprise-level switches support this port mirroring. However, if you are deploying an NSM capability into a small-office or home (SOHO) environment, you might not be able to spend the type of money required to purchase these expensive switches.
Fortunately, there are a few SOHO level switches that support port mirroring. Now, not all hardware vendors allow you to query products based upon this feature, and it often doesn't appear on the product packaging. This can make it difficult to locate affordable hardware with this feature. One resource I've really grown to love is this listing of switches that support port mirroring, from Miarec. The listing includes a lot of the major brands like Cisco, HP, Dell, and more so that you can find a model from a manufacturer whose products you like.
Personally, I've always had really good luck with Cisco, D-Link, and Netgear SOHO switches for use with NSM sensors. Regardless, there are plenty of options that will allow you to have port mirroring functionality for less than $100 bucks.