If u only plan on doing this, this time id just pay the 20 bucks. Gonna cost at least 40 bucks for the initial stuff - connectors, crimper, stripers, wire snips, pins, housing, wires etc..

Takes a while to get good at making connectors as well.

Good skill to have though
I can send u some part numbers later, when i get back.

probably easier to go this route with speakers, if it were power cable then I'd go with pins.
z- connectors
4 pin
https://www.pinballlife.com/index.php?p=product&id=2446
2 pin
https://www.pinballlife.com/index.php?p=product&id=2095

housing
4 pin
https://www.pinballlife.com/index.php?p=product&id=1594
2 pin
https://www.pinballlife.com/index.php?p=product&id=2461

you can use a flat tip screw driver to punch the wire and then snip the excess
or
crappy punch
https://www.pinballlife.com/index.php?p=product&id=2997
better punch
https://www.pinbits.com/index.php?main_page=product_info&cPath=30&products_id=335&zenid=db6a1c179295bc0069c4ac0c6d056c0c

mouser , digikey , Newark or greatplains electronics would probably be the place to go if you were buying a lot of this stuff.
you could also find a better punch on those sites as well

I think the gauge wire you need is 18 gauge for speakers, up to you if you want to keep the colors consistent with the game. (if your going with aftermarket speakers might go with 16 gauge wire)
aren't they white/black stripped?
If I get stripped wire I go with
http://www.asapwire.com/searchresults.asp?cat=759
it's more expensive, but easier to distinguish if you have a lot of wires. I like asap because the jacket thickness of the wire is more in line with what they use in pinball/ arcade machines.

could go with this
https://www.amazon.com/StrivedayTM-Flexible-Electric-electronic-electrics/dp/B01LH1FQJ0/ref=sr_1_6

it's usually pretty thick though.

lastly there you could check the electronic stores
I already applied the filters

https://www.mouser.com/Alpha-Wire/Wire-Cable/Hook-up-Wire/_/N-5ggs?P=1z0zo8oZ1yx79kqZ1z0x86h&Keyword=hook+up+wire&FS=True

copy the link starting with https://
not sure what's going on.