Samtec will sample small quantities of parts (usually no more than 10 of each. However their web site is confounding. If you want to find a part number, request or download a catalog first. When you are ready to order, use the Samtec Sample Form Put in the Item number and Quantity only. You don’t need the pull-down menus or Build a Part Number button at all.
Here’s some part numbers you may want:
Strips of 32 female headers with standard 100 mil breadboard spacing: SSA-132-S-T
Strips of 32 male headers with standard 100 mil breadboard spacing: TSW-132-07-G-S
Strips of 10 2mm female headers for XBee radios: MMS-110-01-L-SV
Strips of 20 2mm female headers for Lantronix MatchPort: MMS-120-01-L-SV
Sockets for 28-pin Arduino chips (low insertion force): ICA-328-ZSGG