im building my first desktop and the motherboard im getting doesn't have onboard wifi.
does that mean i have to get a wi fi adaptor to connect to the internet?
If you can site the PC near enough to the router to use an ethernet cable, that will be a much more reliable connection (slightly faster too) than using wireless. WiFi is rarely used on a desktop PC, that's why most desktop motherboards don't have it. You only use WiFi on equipment that's portable or pocketable, obviously because a wired connection wouldn't be practical or even possible (in the case of a cellphone, for example).
i cant get my ethernet cable to the place im gonna put the computer.
what would be a good wifi adaptor under 20$ canadian?
also i would be about 25 feet from my router
If you can site the PC near enough to the router to use an ethernet cable, that will be a much more reliable connection (slightly faster too) than using wireless. WiFi is rarely used on a desktop PC, that's why most desktop motherboards don't have it. You only use WiFi on equipment that's portable or pocketable, obviously because a wired connection wouldn't be practical or even possible (in the case of a cellphone, for example).