Tourbuzz converts dollars into Credits. Credits are $1 each if purchased individually, and $0.80 if purchased in bulk (starting at 150 credits). This means that a tour will cost $15 if paid for individually, or $12 if credits are purchased in bulk.
There is an additional cost if you wish to convert a tour into a YouTube video. It's $3 for a Branded video, $3 for an Unbranded video, and $5 when you purchase branded and unbranded together.