good idea about retiring early im all for that, I would not buy a claim without testing it first , ask to spend a day dredging with the seller or find an area with a gold history and test it and take out your own claim its not hard costs a few bucks tho
There were a few Tasman claims for sale on trade me last month for around 30k plus. add liability insurance and a dredge suitable for area, access agreement costs ect may be another $15k - $20k depending on dredge.