I'm finally starting to keg. And I've been brewing for about a year. I've got a batch in the primary that will be my first batch to be kegged.
Batches of bottles: i have about 120-140 bottles. I really didn't need anymore. My brews were drank fast enough, and if they weren't, I'd rack a batch to a secondary, and let sit there until I had enough empty bottles to fill. Definitely, definitely ask all your friends to save you their brown pop-top bottles. If your friends drink beer, you'll be blown away how fast you have more bottles than you need. It took me like 3 weeks before I told me friends to just recycle them again.
As for kegging. You're not missing out on much brewing experience by skipping bottling all together. It's more of a money/space issue.
If you have the money to buy a kegging setup, and the space to put one, go ahead. If not, bottling is still your best bet.
If you're looking for a cheap way to get a bunch of bottles: Throw a microbrew party. Ask all your friends to bring over a 6-pack or two of a craft beer. A. You'll get to try a ton of different craft brews, B. you'll get a TON of bottles.
As for me, i'm kegging, and never looking back.