My 2002 Chrysler Neon LX has an 'old type' push in antenna, and unfortunately has seen better days! It now won't push down or up - which means I can't take the car in the car wash for risk of bending or breaking it.

I'd like to replace it, either with same type - or if possible, an up to date one (even maybe electric) - but heard it could be a big job(?)

Can anyone advise if this is true - and how much (roughly) this might cost??

 

You might try straightening out the old one by hand. I was able to get my power antenna on my Mercury Sable to straighten out and start working again by VERY carefully bending it using only my hand, no tools. The secret is to use only the force necessary, applied only where needed, in the correct direction. If it's kinked, then don't bother.
Look on the net for replacement masts if you can't fix it.
Don't bother with a power antenna. The radio probably doesn't have an outlet to control it and the motor will need extensive wiring and room to install it.