No idea on what to charge. Check with your area Vets on what they charge per day for boarding.
Some things to consider:
1. Would someone be at your "kennel" 24/7 or just occasionally?
2. Would you include feed & all as needed?
3. What about liability release from customer if anything happened to their dog? Would you have insurance? Would you board any potentially "aggressive" breeds?
4. Would the dogs have adequate exercise area, shelter from weather?
5. Would the dogs have health papers (all vaccinations, including dystemper, parvo, rabies, etc.) and a Vet's Certificate prior to bringing them to your place?
6. Would you board any "high maintenance" breeds that required daily brushing, grooming, etc.
7. Would any of the dogs be "indoor dogs" as opposed to the usual "outdoor" type dogs?
8. Boarding toy, small, medium, large, extra large dogs? Each size would require different accommodations.
I would think that any private boarding place would need to charge at least $2.50 a day to make it even close to worthwhile. Probably closer to $5. a day. Dogs are usually higher maintenance than cattle.