Will iMac automatically boot from USB stick if the HDD is blank?

I am going to buy and install a new 1TB HDD (I cannot afford to buy a SSD+External) to replace my iMac's dying stock 320GB HDD. It is a 24" early 2008 iMac, with 4GB ram, running Yosemite.

I do not have a wired keyboard; my current keyboard is apple's Bluetooth wireless keyboard. I used a friend's wired keyboard once so I could use the appropriate startup key combinations when I needed to boot from a USB stick, but they are not around anymore. I have tried all kinds of things and I cannot do any of the startup key combinations with this wireless keyboard!

I was hoping to install OSX Mavericks (via USB stick) on the new blank HDD (I started having problems shortly after I installed Yosemite). Because the iMac will not be able to boot from the HDD (because the HDD will be blank), will it automatically boot from the USB stick? And once it does boot from USB, will the bluetooth keyboard work as I go through the install process? Or do I have to get ahold of or buy a wired keyboard? Or is a mouse sufficient? And, if I have to get a wired keyboard, what is the cheapest wired keyboard that will be compatible / able to get the job done?