Welcome to the club!
So here is the 2-cents you didn't ask for from a technical perspective:
1998 and 1999 models are going to be more problematic at this time due to age and the quality of many of their parts being "first run," meaning the interior is going to look like crap. Also if it's a diesel you are after, the 98 and 99 have a known "hot start" software flaw that will take some $$ to resolve (as the 98 and 99 ECUs cannot be flash reprogrammed, they must literally be 'chipped' as in opened up and their memory chips removed and replaced with new ones!)
The 2.0L is a pretty indestructible motor. I think 2001 is when they moved to the drive by wire electric pedal, all prior models are drive by cable. The 2.0 does consume some oil (as can the 1.9L TDI diesel). The 1.8T, with exception to the Turbo S 2002-2004, was a slower variant of the 1.8T found in all other VWs including the GTI. I have historically said not to mess with them as they seem to be very problematic but we just bought a 2001 1.8T passat with 106,000 miles that is in good condition. I have $6800 in receipts that show many many MANY cooling system repairs over the years (mostly failed flanges and hoses). More so than I've seen for a 2.0 or TDI.
A word on interiors.... a 15 year old car will have a worn interior. Expect a sagging headliner (A fun DIY Job, or just use push pins to hold it up), worn seats (easy to replace with units found at your plentiful pick and pull junk yards), and probably blown speakers (also easy to upgrade). Broke window switches and mirror control knob, glove box latches, arm rest latches, and "static" cupolders (98-01) are VERY common. Be prepared to scout out some replacement parts.
2002 featured a swivel cup holder that, I personally believe, was the best design ever and nothing has ever surpassed it. It's easy to upgrade (or downgrade if you have an 06+) to it, but sourcing one can be an issue. Again, pick and pull yards, this site, and VWVortex will become your friends.
Lastly, I'd really advocate the manual transmission. The O1M automatic is not a stout transmission, but I have seen all three engine combinations make it to 150k and even 250k miles if well cared for -- and well cared for is involved, and I argue, expensive. I've never replaced a clutch in a Beetle, except in my 2003 when the automatic transmission was pulled out and a manual transmission replaced it. I've gone 250k on a clutch before (not entirely in my ownership during that mileage time).
But no matter what, you'll love it and its quirks. The beetle is the only car where problems are personality, and quirks define the experience.
Oh, yes, the alarm. Your door sensors will likely be toast. When you unlock the car put the key in the ignition and turn it on within 30 seconds. If you don't, the car may re-arm the alarm and cause you a headache when you do try and start it (this happened to my mother in her 99 this past week). China made replacement door lock modules are $30, but are very involved to replace per door. Easier to know the failure and how to work around it, in my humbled opinion.
Cheers!
Since then I've had my share of minivans, crossovers and school buses (I'm a school bus driver). I'm a married mom and foster mom who's always last in line to get anything. Now I'm being a little greedy. I'm turning 40 this year and I'm scraping up a little money to buy my very first Beetle. The primary use for my Bug will be to drive around (maybe doing errands) with none of the other 6 people that live in my house in it. 
