I have come to hate manual transmission trucks since owning this, employees tend not to know how to drive them and thus the clutches always burn out, however Toyota has engineered this truck to be a cake walk to fix. We can have a new clutch installed in about an hour or two. Speaking of reliability this truck rarely let us down, there was one problem that lead to a wheel coming off but that didn't damage the truck it just left us on the side of the road (Toyota issued a recall the next year for them). All we did was change the fluids as we desired, replace the battery at 200k, spark plugs at 150k and Alternator at 220k.
By the time we were done with this truck the bed was rotting away, every panel was dented and scratched, the seat was worn to the foam, but the motor ran like new, the truck passed smog and shifted great, mechanically it was in great shape. Let me be perfectly honest with you, we (mostly employees) abused this truck very severely, fluids weren't changed on schedule, we never even replaced the timing belt (every 100k it's supposed to be replaced), it looked like it was used to play bumper cars, it was over loaded for its weight class, it was driven on horrible Northern California pot holed roads, and it didn't skip a beat. It's hands down the most reliable vehicle I've ever owned.
In conclusion: If your just starting out you can't go wrong with buying a new or used Toyota Tundra, they make great delivery & pump trucks for the company on a budget. You can easily find parts at the dealer, junk yard, etc and they have the most important feature of anyone looking to buy a service truck, RELIABILITY.