Hey there Lyns,
Depending on the generosity of your firearms dept,you will get 1300 to hold 1000 to buy...but in my experience a first time applicant will probably get 500 to hold 500 to buy (in my neck of the woods anyways). Always put down more than you anticipate using that way you if you do get lesser amount it may not be the minimum, which i think is about 500. It all seems to depend on your local dept.
Once applied to your FAC..that is all you can get...you just need to get it signed when you buy ammo. I will tell you though that page gets filled pretty quickly when only buying in 500's especially when you've got a 15-22...
I hope your ammo salesman has very small handwriting haha.