I wouldn't say the keyboards or mice are particularly rare at all. Most of the ones I've ever seen for sale are the beige variety. They turn up on eBay all the time. Here's a beige 1984/86 mouse for $.99. On the extreme high end of the spectrum, Robert2d3d has a more common platinum one for $39.00.
The mouse by the way connects to the far left 9 pin serial port (as you look at the ports). Never plug the mouse into printer and modem ports and vice versa. While most of the Apple serial peripherals omit pins on unused ports and avoid conflicting with damaging configurations, there are no guarantees. The proprietary keyboard and 9-pin mouse connectors persisted on the 128K, 512K and Mac Plus. The Plus introduced the round Mini-Din-8 serial printer and modem port, which had been standard 9-pin serial and prevented confusion with which port to plug in the 9-pin mouse. The Apple IIGS was the first computer to get the new ADB connectors, followed by the SE and Mac II. They ADB and non-ADB equipment are not compatible and there are no adapters to use one with the other. Ironically, the ADB port's similarity to the new Mini Din-8 serial ports led to confusion as to where to plug the mouse and printers.
As for keyboards, starting on the extremely high end, robert2d3d will sell you n authentic 128K beige one right now for $129.00. On the low end of the spectrum, there's one on eBay right now for $15. Littlejohn918 offers both the 128K model and the beige extended keyboard modelfor $4.99.
So you see, they are very easy to come by, should you find yourself without. It's all a matter of how much money you want to pay and how quickly you need it.
The mouse by the way connects to the far left 9 pin serial port (as you look at the ports). Never plug the mouse into printer and modem ports and vice versa. While most of the Apple serial peripherals omit pins on unused ports and avoid conflicting with damaging configurations, there are no guarantees. The proprietary keyboard and 9-pin mouse connectors persisted on the 128K, 512K and Mac Plus. The Plus introduced the round Mini-Din-8 serial printer and modem port, which had been standard 9-pin serial and prevented confusion with which port to plug in the 9-pin mouse. The Apple IIGS was the first computer to get the new ADB connectors, followed by the SE and Mac II. They ADB and non-ADB equipment are not compatible and there are no adapters to use one with the other. Ironically, the ADB port's similarity to the new Mini Din-8 serial ports led to confusion as to where to plug the mouse and printers.
As for keyboards, starting on the extremely high end, robert2d3d will sell you n authentic 128K beige one right now for $129.00. On the low end of the spectrum, there's one on eBay right now for $15. Littlejohn918 offers both the 128K model and the beige extended keyboard modelfor $4.99.
So you see, they are very easy to come by, should you find yourself without. It's all a matter of how much money you want to pay and how quickly you need it.