Re: First Bokken
I'd agree with Paul, as I also own a cheap $10 red oak bokken, and it seems to have worked well for the past few months.
That said, our dojo mostly does kata work about every other class, and we don't whack our bokken together all that much. One reason for this is that (as I understand it) you're not supposed to let your bokken get whacked, even in faster or harder practice. The point is to blend your movement (and blade) with the other person's instead of incessantly banging swords together. Even katana were prone to breaking if hit from certain directions.
That's just my thoughts, of course. I'd advise finding the best possible compromise between your sensei and your bank account.
Yours in ukemi,