We have an arcade like this. The claw machines are rigged. The arms never grip strong enough to win. The most I've lost in there was £2 before realising it was rigged.
We have ticket machines elsewhere. Again - my children know that there's roughly 20p return for £2 worth of spend. So a £10 later, and a fun day out (some of the machines are quite fun) - they come away with sweets from the tickets.
There is a gaming console in for stupid amount of tickets, but no-one will ever win that.