I've always been amused by that myth. Your claim is worth what your claim is worth. It's not worth more just because you have an attorney, though personal injury attorneys insist that it is. I used to routinely slice the fat out of attorney demands and got claims settled for less because the attorney wanted his payday.
If you hire an attorney by the hour you'll very quickly rack up bills in the $10,000 to $20,000 area and your claim may not be worth even a fraction of that if it's worth anything at all.
By the way, just because your slip and fall happened doesn't automatically make the business owner liable.
I suggest you post your details and I'll tell you if you even have a claim as well as whether it's worth hiring an attorney at all.