How much would it cost to sue Taco Bell?

It's hard to tell how much it would cost.  Cases like this are normally handled on a contingency, meaning the client pays no out of pocket legal fees, but only a percentage of what he/she gets in settlement or after judgment.  However, you would still be responsible for paying disbursements (filing fees, court reporter fees, expert witness fees, etc.)  Moreover, your attorney will have little control over costs.  Your attorney can write a letter and the defendant can agree to settle right away.  Or, the defendant (particularly one with deep pockets) can refuse to make any reasonable settlement offer, insist on extensive discovery, make multiple motions, and thereby delay the case and force you to spend money on the types of expenses listed above.  Your lawyer can't control how the defendant responds to your claim. You didn't ask this, but I don't think your girlfriend has much of a case.  The only damages you mention are that she vomited.  You don't claim that she had any medical expenses or had to miss work or any other monetary damages.  I think she'll have a hard time finding an attorney to represent her on a contingency.