I am in the process of redoing the audio in my 2000. I am probably over what would be considered a budget install. I also reached out to some knowledgeable people on here for advice. I added new 5 1/4 speakers in the dash and soundbar. You can go bigger in the soundbar (6.5 maybe?) but I decided to spend the extra money for a better quality 5 1/4 than lower quality larger speakers.
To swap the front speakers to 5 1/4 you need an adapter, they are cheap on Amazon or eBay. I actually have a spare set I can send you if you want to pay shipping, but new it was only $12 with free shipping on eBay so I don’t think I would really be saving you much money.
I went with a cheap Amazon media player that supports car play. I have my top off whenever possible so I figure if someone wants to steal it, I won’t be too upset. I went double DIN which requires a kit with a new dash center piece. So more $$. I assume they have single DIN options, but I never looked, because I knew I was going double.
For speakers I went with Blam, a lot of people here rave about the polks and they are priced right. If you search for Polk in the forum search you will find the specifics.
I put an amp buried in my dash, it is out of sight and it would take too much work to steal. That’s how I am getting good sound with a cheap ass head unit. The amp was about $100 on Amazon.
I don’t have a sub yet, the plan is a powered sub with built in amp that will get bolted inside the back seat frame. Once again out of sight. But honestly it already sounds so much better that I am not in a rush and have other priorities for Jeep funds at the moment.
I also had speakers that weren’t working. I went ahead and ran new wire to all four. I wasn’t sure if it was the speakers or wire causing the problem but with the amp I wanted a larger gauge wire anyway.
You can choose what you want to do and spend less than I did. I think I have spent about $650 so far with the new media player, dash kit, 4 speakers, amp & installation kit, wire and various odds and ends.