Welcome to the forum.
I understand your desire not to spend too much on the first machine but there is a danger of going so cheap that you soon find what you've built is inadequate for your needs and much of the initial spend is wasted as you buy better replacements. That's exactly what I did.

You haven't said what size machine you want to build but going for reasonably beefy motors immediately, even for something quite modest, will future proof your investment. Same goes for motor drivers and leadscrews.

Note that cost rises exponentially with the size of the cutting area so decide what you want to make with this machine and size it to what you actually need.

You will also need some software to control the machine. MACH3 is very popular but LinuxCNC is free!

Kit