It's difficult to come up with an average number for how much suing someone costs, but you should expect to pay somewhere around $10,000 for a simple lawsuit. If your lawsuit is complicated and requires a lot of expert witnesses, the cost will be much, much higher.
I would just hint with out naming names or trademarks, etc.
Generally I wouldn't recommend it though without really good and proven reasons.
And make sure you have someone that knows their stuff fact check as people often misunderstand whats true/correct when attached to a business emotionally.