Hi,
First of all, what kind of printer/scanner are you looking for? A monochrome or colour printer? Laser or inkjet?
The problem will be finding printer and scanner drivers/software compatible with OS X 10.10 Yosemite (released 2014). You may have to look for somewhat older printer models. If you find a printer of interest (new or used), go to the manufacturer's support pages for the model in question and check whether drivers are available for Yosemite. You could also post back here with the exact printer model, and we can help you.
It is also worth mentioning that the AirPrint technology from Apple allows printers to be used without additional drivers, provided that the printer and the Mac computer are connected to the same network (Wi-Fi router). AirPrint works with wireless (Wi-Fi) or wired (Ethernet) network connections.
About AirPrint - Apple Support
AirPrint can be used with operating systems as low as Mac OS X 10.7 Lion, so OS X 10.10 Yosemite should be OK per se. However, a printer manufacturer may provide extra software with higher system requirements for setup, ink management, and similar purposes.
An ICA driver may be needed for scanning (via Image Capture). If necessary, there is a third-party commercial scanner driver called VueScan.