How much the replacement usb charging port

Erm, I’m not sure how to interpret your question, so I’ll answer all of my interpretations.

1. ifixit is not a repair shop, you can’t send your device in and get it fixed. You’re the person who fixes your stuff :)
2. TI wont fix your calculator, they’ll probably just try to replace yours or sell you a new one.
3. If you have the skill to repair it yourself, I found some replacements on Amazon for about $10 although I’m certain you can find much cheaper alternatives on other sites.

Before I go into how you’d replace it, I want to make sure that it’s the port that’s broken and not something that’s much easier to replace. Have you tried using a different Mini USB to USB type A cable? Does your current cable charge other devices just fine? Have you tried plugging it into a different power source? i.e. instead of plugging it into the wall adapter, try plugging it into your laptop (and vice versa). If you’re sure it’s the port, then here’s how the replacement process will probably go for you. Only attempt this if you are comfortable with soldering! Or if you don’t care about accidentally breaking your calculator more. (NOTE ''''I have never attempted this exact repair before)

Here’s a picture I think you’ll find useful:

1. Remove the battery.
2. Remove the 2 screws hidden underneath the battery. They require a phillips head screwdriver
3. Remove all 6 screws on the back cover (note: they are Torx T6 screws, you’ll need a special screwdriver to remove them)
4. Remove the back shell from the calculator.
5. This is where my knowledge of the hardware of the calculator ends. I’ll still try to assist you through taking it apart though.
6. Carefully remove the display ribbon cable from its port
7. Remove the motherboard (you may need to carefully remove the foil covering part of it, and you may need to break some plastic because the motherboard is heat-melted to the case :( )
8. Now with the motherboard free, you should be clear to inspect the damage to see if replacing the mini USB port will even fix anything. If you think (or are unsure if) it’s just the port and not something broken on the motherboard, desolder the mini USB port from the motherboard.
9. If you need help desoldering, refer to this video. If you don’t have a solder-sucker, try referring to this video.
10. When you desolder the broken port, you may be able to inspect the motherboard more closely.
11. Now with the broken port off, you should be able to solder on your new port.
12. To put the calculator back together, place the motherboard back in its spot. (You may want to plug in the display cable first)
13. Put the back shell back onto the calculator but don’t put in any screws yet! You may need to take the shell off and re-adjust something.
14. Place the battery back into its compartment, if the calculator turns on that’s a good sign! Now plug the calculator in to a power source, if it starts charging then congratulations, you fixed your port!
15. If the calculator does not turn on, take out the battery and remove the back shell to make sure you plugged everything in correctly and that there’s no damage to any of the components. You can also try referring to the Recovery Techniques guide. If nothing works, then you may have accidentally damaged a critical part of the motherboard and you’ll need to contact TI Support to see if they can somehow fix your calculator, or replace it.
16. If the calculator still does not charge, then the problem is most likely not the port itself, but rather an irreparable component of the motherboard. You’ll need to contact TI support to see if they can replace your calculator.

Good luck with your repair!