There are about 4-6 buses to go from Arequipa to Cabanaconde. It cost 30 (8€) soles.
Meditate and relax yourself, a looooong and unconfortable 6 hours travel is waiting for you. The road finishes in Chivay, the main city in the canion. After that the road is full of pot-holes.
The only one possibility to reach the Canyon of Colca is taking part of an organized excursion, or those are the info I know...
So, just enter in any travel agency in Arequipa and BARGAIN!
Usaully the transports are made with a 4 x 4 Jeep (essential!!!) but the one I got, had also an ossigemn box...just in case, you know...you will get to 5.200 mt!
I would say I was happy enough with Pablo Tours but if I was to do it over again, I'd do it by public bus. The tour was $45 per person and included the guided tour to Chivay, lunch, breakfast, and accommodation there. You had to get dinner on your own. They took you to the hot springs and some had to pay to get in there, other (like us) didn't. The second day you get the guided tour bus to Cruz del Condor. The guide was not very good in English and we all felt she made a major blunder in having us hike to Cruz del Condor as we nearly missed the condor and it was gone by the time we got up to the actual lookout! It would have been just as easy to go there first and do the hike back to the bus. Those on the two-day tour went back on the bus too. We got a guide who walked us to Cabanaconde for lunch and then down to Oasis. We got dinner and our "room" there. We also were provided with breakfast and the guide brought us back up to town and got us our free bus ticket back to Arequipa. I think it would be slightly cheaper on your own and you would have more freedom to stay in a place you liked an extra day. The bus ticket back was only $2 so the transport would only be $4 round trip and the accommodation and food would maybe be $30 and that would be an overestimation. So, if you are adventurous, just do it on your own. If rushed like us, the tour is a good option but make sure to do at least a two-night one, and I’d even do three if you have the time as you see more of the bottom of the canyon.
As in anywhere in Peru, there are several local buses plying the routes of the Colca Canyon so there is no need to go in a tour. The transportation costs about $1 USD or less per hour traveled on bus. For those headed to Cusco, there is no need to backtrack to Arequipa for in Chivay you can buy a direct ticket to Cusco.