What I did (before I got someone to pay for it for me :D) was buy an iPod touch on craigslist. Got it for like $80. It was a big stretch, financially, at the time, but the hours upon hours it saved was well worth it. You can also sometimes pick up iPhones with bad esns/cracked screens for a lower than normal cost.

'Course all of that assumes you would need more than 2 months worth of debugging on browserstack.

Good luck, either way