To ensure you're booking a legitimate and reputable budget trekking company, consider the following:  a) Check online reviews and ratings from previous trekkers.  b) Look for companies registered with the Nepal Tourism Board or other relevant authorities.  c) Inquire about the company's safety protocols, emergency procedures, and their guides and staff's experience and qualifications.  d) Compare quotes from multiple companies and be wary of prices that seem significantly lower than the average, as this may indicate a lack of proper services or support.