Thought i'd post this tool guide, not entirely sure if it's all correct so if you guys could do research for me and see if anything's wrong, it would be greatly appreciated ^_^
Axe: 400 bells from Nook's shop
Silver Axe: Serena (after throwing an axe into the town fountain)
Golden Axe: Serena (after throwing an axe into the town fountain)
The Difference: Silver axes will never break. Golden axes will also never break, and cut trees down much faster.
Net: 500 bells from Nook's shop
Silver Net: 500 bells from Nook's shop (after level 2 upgrade)
Golden Net: From Tortimer after catching every bug.
The Difference: The silver net is a bit bigger than the normal net, while the golden net makes catching bugs 'a breeze' whilst being bigger than the silver net.
Shovel: 500 bells from Nook's shop
Silver Shovel: Resetti's surveillance center, which can be accessed any time between 8 and 9 PM. The center is on the right side of the city. The traffic cones will be moved when it's available for entry.
Golden Shovel: Bury a shovel for 1 day (24 hours), contrary to what the guide says (Four days)
The Difference: A silver shovel gives you a 10% chance for more bells when you're smacking rocks. The golden shovel allows you to plant bell trees, but does NOT give you the chance for 10% more bells.
Fishing Rod: 500 bells from Nook's shop
Silver Rod: 500 bells from Nook's shop (after level 2 upgrade)
Golden Rod: From Tortimer after catching every fish.
The Difference: Silver rods have better lures than normal rods, making fishing a bit easier. Golden rods 'is a real fish magnet!' plus makes the fish hold onto the bait for a little bit longer.
Slingshot: 500 bells from Nook's Shop
Silver Slingshot: 500 bells from Nook's Shop (after level 2 upgrade)
Golden Slingshot: Balloon (after shooting at least eight balloons)
The Difference: The silver slingshot fires two bullets instead of one, while the golden glingshot fires three.
Watering Can: 500 bells from Nook's shop
Silver Watering Can: Mailed to you from Posy Farms, after buying 50 flowers from Nook.
Golden Watering Can: From town hall after maintaining a perfect town for 15 days straight.
The Difference: The silver watering can revive wilted turnips and it's also rumoured to keep flowers alive longer. The golden can has the ability to create golden roses.