To start first: I am working for trekksoft.com – that means I am working for one of the companies who does offer a online tour booking solution, just to point that out!
By doing this job I invested so time to get some informations about the actual market, here are my insights:
1) www.rezgo.com – I guess the biggest company in the market – they offer similiar to trekksoft.com a pricing model based on a fee on every transcation
2) www.checkfront.com – they have a pricing model which is based on a monthly fix fee
3) www.tourcms.com – also here a monthly fix fee
4) www.27bards.com – this guys have a monthly fix fee plus a fee per booking
Obviosely all these companies do offer a basic functionality : you can offer online bookings and set up easily new tours online. With trekksoft.com we are also in this market and we are a competitor of these companies. From our point of view the unique functionality we do offer is a integrated payment gateway. That means you don`t have to install a PSP (Payment Service Provider) Account, you just can start right aways by registering under www.trekksoft.com