Hey, welcome.

There's a good bit you can do as far as inexpensive mods go, especially if you do the work yourself.

Interior:
Door panel inserts
Different steering wheel emblem
Change gauge color
Change climate control color
Paint center console
Aftermarket radio
Bluetooth transmitter
Upgraded speakers
Custom headliner color
Tint
New shift knob
New shift boot

Exterior:
LED/different color headlights
Front lip
Paint wheels
Muffler delete/eBay exhaust
eBay Intake
Tint tail lights
Tint Sidemarkers
Change/delete emblem colors

That's what I consider cheap (~$100 or less). I'll see if I can think of more.