bonus whores reccommend starting at
bet365 for bankrolls of $50-200,
but you need to play at 0.5/1 NL or 1/2 limit to clear it properly.
if you follow thier advice i think you may be under bankrolled and risk going bust.
i would prob reccommend
ultimatebet, or
pokerstars for a good choice of low limit games. i do not think stars has a bonus right now but UB has 20% and it clears at any limit.
also VC is another site where you can play low limits and the bonus (25%) clears at all limits.
(feel free to use me as a referal let me know and i'll pm the info)