The negative wire and battery connector to my Mazda 626 need

The negative wire and battery connector to my Mazda 626 need replacing. Is this something a layman could do?
The car is a Mazda 626 LX, 1991 aka "the deathtrap" . Walmart just replaced the battery, but said that they do not have the parts to replace the negative wire and the connector that leads to the battery. just, what they showed me was that the connector to the negative port of the battery was all corroded and crumbly, and the wire coming out of the connector was old, crakced and frayed. Both, they said, should be replaced, though the car and battery now work.

I guess usually what I am asking is, if you do not know lots about cars, is this something that may be done, or is this asking for catastrophe and am I supposed to just pay a mechanic to do it?

Thanks.

This is a rather straight forward task, remove both leads from the battery, follow the negative lead toward the engine, you will find the other end bolted to the block. Remove this screw and remove old cable, install new cable, earlier PRUCHASED, follow path of old cable and reattach leads to battery.
If you can not buy a prefabbed cable, you'll have to buy an "eye" connector for #6 or #8 guage cable, the cable, two three feet make sure to state that it's for battery use, and the proper connector for your battery, top/side post or screw in, and you will also need a round punch and hammer compression tool to secure the "eye" connector to the engine side of the cable, using old cable, cut new one to length and attach new battery connector, now install as earlier portrayed.
If you aren't comfy doing this yourself, I could propose you take your car to a "battery" shop, they can have you fixed up in less than an hour.

15+ yrs. auto mech.

sure you may be able to do it .but do not expect your car to run afterwards..or your windsheild wipers to turn on when you open the door..etc..take it to a pro.electrical is nasty stuff

if you have the tools and hardware, you may be able to. I did, that is so strange, I had a 91 626 also. for reals. seriously, you guys.

Yeah you sure could. All you must do is remove the cable from the ground, sand down the area where it's grounded so you make good contact, replace the cable, add the connector and hook it up to your battery. Pretty simple.

I think that all you must do is get a new lead connector. Then cut the wire some inches back and strip it so some of the newish wire is exposed. Then get an adjustable wrench and attach the new connector, then attach it to the battery. Maybe use a wire brush an where it connects to insure a good connection. If you may be able to install an outlet or switch you should not have any problems. If not, maybe get someone to do it for you.

You could just replace the terminal to the battery but what happens is the cable itself will also corrode and the wires will look hard but inside the appear like sponge. This may be up the wire some number of inches. I could order the part from Mazda and replace the whole thing. It typically terminates on the engine someplace on a bracket etc. A set of cheap metric wrenches, some sand paper to clean the spot where it connects and you done in 15 minutes.