100 bundles? Wild guess ...

How dare you own a PayPal before your 18th birthday. I'm gonna report to PayPal right away!

maybe Justin Bieber will come to your house and steal you from your parents for doing this

Soooo... What are you gonna buy? :p

On a serious note, I've done multiple small purchases with paypal (like 12 purchases) and Paypal didn't block me or anything BUT my bank stopped all transactions until I called to let them know I was making all of those purchases. It was because they thought someone had stole my CC.

Are you going on a bad rats buying spree?

Yup, just do it I do the same

Is it just me, or does this sound really, really shady?

+1 Shady.

Also they might call you to verify that you're actually making the purchases, otherwise they will be happy to just keep charging you fees.

Yes they will, after the 9° purchase in a row I believe, they block your account and asks for personal info, but nothing serious, just card numbers, id card, these things.

What will most likely happen is your account will be temporarily blocked until you call them. PayPal have a stupid fraud alert system that even they can't override, so even if you warned them in advance it probably wouldn't help.
Also PayPal staff are awful to deal with, so be warned. (I've had to deal with them WAY too many times)

You can buy 100 porn movies without problems, relax.

Online drugs... What the fuck are you on atm?

WHERE are you buying whatever it is from? There may be other options that make it so you don't have to do individual charges to paypal. For instance, if you're buying things from steam you can add the money to your steam wallet through a single paypal transaction and each of the individual purchases are just drawn from your steam wallet. I did this when I bought 100 copies of fortix and it went much more smoothly. If it's something other than steam and they don't have a "wallet" feature, you could do something like using paypal to purchase a prepaid card for whatever amount you need since prepaid cards are much more lenient with their restrictions and security protocols. Doing a crapton of small purchases is a flag for "freeze the account there may be fraud goin on" for most money services.

I do hundreds of small purchases a month through ebay and dont have a problem but that could be because paypal is run by ebay.

What ive had to deal with before, all the online checks are to see if it is you that has control of the account. save all your purchase history so that you have it to hand if they want to ask questions about it, they may demand you connect it to a bank account to prove ID (not age) and country of origin is correct.