External Pickups?

I want to know how an external pickup sounds compared to a normal one?
Where can I find an external one and how much do they cost normally?

You can find out more about them here

I have one, and it works well... But I have a hard time keeping it on the ukulele...

Price, thats tough. Average is $50 from what I see... I got mine for 15 but I was lucky to find one used on ebay...

is there a certain kind needed for a uke?

The one Aldrine is using in the video is the one I have... But really the externals that work for the uke are the ones that "stick" on... I don't believe any of the sound hole ones will work...

what is the brand name/ model of the one you and aldrine use

Nylon-stringed instruments need a transducer pickup. Acoustic guitar sound-hole pickups do not work. They are too big anyway. The problems with stick-on pickups, in addition to being possible to knock off the instrument if you move around much, is that they are noisier then internal designs. If you are a sloppy player, recording with one will tell you right away. Aldrine can use them successfully because he has superb technique. I'd opt for an internal pickup and among those that work on the ukulele, LR Baggs are the best in my opinion. They are not cheap, but they are worth it.

You can try building your own for $10 or less. It won't sound as nice as the under-the-saddle variety, but it'll work.

DIY piezo instrument pickup

I would agree with Pippen, LR baggs is the way to go. Burnt the extra cash on one for my acoustic and have never looked back, sounded alot better than the Dean Markley I had in there before. The DIY route will work, but it will essentially be the same as the whole stick on thing mentioned.