Yes, after all, you are running a commercial entity not a NGO to cater to the needs free of cost. You meet your costs and take a certain amount of margin as well. Otherwise, your operations cannot be a viable one. You can charge a reasonable fee both from the Employer as well as the candidates. What's more important here is, you shouldn't be harsh on the poor candidates in fixing the fees. Whereas with the employer you should be competitive as well as smart in the selection of candidates to meet their requirements, honest and timely. In the competitive world, you are likely to face stiff competition among your peers and above all winning the confidence of employer which only will enable your firm to rise above the rest which is secret of success. Rates depend upon what's prevailing in the sector more so goes well if you can accept rates acceptable to your employers.