97 Ranger--Oxygen Sensor

I've got a 97 Ranger in need of a new O2 sensor. I was wondering how easy this is to replace without taking it in. I live up in the mountains and every place up here is outrageously expensive.

If anyone has any input, I would appreciate it.

Thanks,
Matt

the O2's aren't bad to replace - you need a special socket or a very good quality 7/8" wrench but that's it for tools - being double jointed seems to help sometimes to get to the plugs - and you have 4 oxegen sensors on your vehicle - what one or ones are you in need of?