May I ask what it is about hermits that interests you?
I agree, they can really pinch hard, and it will hurt. They're easier to pick up and move around than most pets because you can grab them by their shell and keep away from their claws. To actually handle them will put you at risk. One of the safest ways to get used to them is to wear jeans and sit with them on the floor, and let them crawl on your legs - your skin is safe, and they can't fall and hurt themselves. You'll be able to learn what they are okay with and what they aren't, and figure out if they are friendly enough to go farther with. I had an adoptee once that I sat with on the couch, and he ran up my shirt and started tearing at it with both claws! I could barely get him off of me, and he stayed in the tank after that.
If you're looking to get 2 hermits, a 20 gallon long is a great starting point and should last two small crabs many years. Off the top of my head:
$20 -glass tank at a $1 a gallon sale
$15 - glass or screen lid for tank.
$25/$30 - Ultratherm UTH ordered online (includes shipping costs) that will cover the entire back of tank
$7 - playsand from hardware store
$5 - cocofiber from pet store
$5 - moss for moss pit (I consider this a must, they love it!)
<$10 - box of Instant Ocean. It's cheaper if there's people with saltwater fish in your area.
<$5 - dechlorinator, make sure it removes chloramines and ammonia
around $15 - shells (craft store, online)
And then the other stuff is as crazy as you want to get. You can use plastic tubs, or buy reptile items:
2 bowls deep enough to submerge with a way back out
at least one food dish
corner caddies are awesome to use any vertical space
hides of any kind (homemade coconut huts, reptile hides)
climbing items (wood, sticks, you can use things from the backyard)
vines
fake plants (craft store)
mister
humidifier (if you need it)
Now, per month it'll be the cost of water and electricity. (Which is not much.) Food costs can be as little or as much as you want - they can eat the same things we can so if you're a meat and seafood eater and have fresh fruits and veggies then they can have a tiny portion of your meals and be perfectly happy. Otherwise you'll need to buy them veggies and fruits (cut into meal sized pieces and freeze so nothing goes bad) and freeze dried insects and/or seafood from the reptile and fish aisle (around $3-$7 per item).
All in all, a really pretty 20 gallon long with items purchased thoughtfully could be had for between $100 and $200. Food costs for year could be as little as $0 and probably more realistically around $30 or $40 for a big variety of things - deep freeze what you buy and that will last for years and years since they eat so little at a time.