The Tiger Cave Temple is accessible by red songthaew from most places in Krabi town. Most foreigners get charged 100 baht to get taken right to the temple. If you don’t want to pay that much, supposedly you can get them to drop you off along the nearest highway for much less.
Unfortunately, when it comes to Krabi and the touristy parts of South Thailand in general, it’s hard to know if the price you’re being quoted is real. On my way back to town from the Krabi Cave Temple, I negotiated a price with a songthaew driver only to be dropped off outside a Big C shopping center! He told me I could easily catch another ride from there, but he still wanted full price! I refused and gave him half.
Getting to the bus station from town was another adventure. Though my hotel receptionist gave me an idea of how much I should pay, 4 drivers in a row wouldn’t give me a price anywhere close to that. I finally found a driver who’d take me there for the normal price. Except just to the closest point along the highway, and not to the actual station.
While Grab does exist in Krabi, the rates are much higher than what you’d normally pay in Chiang Mai or Bangkok.