I once had a Shadowrun group who hit a truck transporting gold, and they walked away with something like two million nuyen (each) in a campaign where that was more than they had combined through character creation and their careers.
It was somewhat of a mess, but it counteracted itself nicely, because I didn't just let them spend it on anything they could afford-they had to justify finding, and purchasing their new gear, so instead of immediately buying weapon and power foci and cutting-edge augmentations and weapons the massive haul wound up sending them on missions to build relationships and find things that they could then spend their money on; in addition to the copious amount spent on outfitting the team with headquarters and new shiny vehicles so they no longer had to take the bus or drive personal vehicles around on their runs.
Basically, look at the windfall as a stepping stone to future encounters; players probably don't have the relationship with the master artificers or merchants who sell the sort of things they can now afford to buy some of the stuff they want, so they'll have to work to it.
Of course, though this doesn't work in every setting, spending a lot of money at one time tends to be frowned upon in certain places, especially when tax evasion or criminal acquisition is suspected.
DnD 4e was balanced around the idea that monsters have an AC around level+14, other defenses around level+12, attacks against AC around level+5, against other defenses level+3. There are slight deviations, Solos have more of everything, Soldiers have more defenses, Brutes have more Fort, less Reflex and attack, but these are the approximate numbers.
On the other hand, PCs should have attacks and defenses along the same numbers. They gain attack bonus equal to half their levels, +Attributes, +Expertise, +Proficency (if Weapon attacks) and +Enchantment bonus from the magic items. The same is true for AC and other defenses.
For this reason it is essential that they have the Enchantment bonus they should, otherwise the level appropriate challenge (according to the DMG) will kill them easily. This is not so big a difference in low levels, no magic or +1 is not a big deal, but +6 or +2 could mean life or death at level 27.
This means magic items are not a story element like in earlier editions, but as an integral part of a character as feats for example. So the question is not whether the Dwarf Barbarian should get a magic hand item, but rather why does he not already have a neck slot item, and how high is the bonus of his Weapon and Armor.
Some people, mostly those with roots in DnD 2nd edition, are not comfortable handing out magic items like candy at Halloween, and think magic items are a gift and something special.
If you are one of them, you should consider introducing the inherent bonuses as described in DMG2 and perfected in the Dark Sun setting book. It takes care of the numbers, and you can keep magic items rare and interesting. It is also a good guide to see what kind of bonuses PCs must have from Enchantment.
If you do not have access to any of these books, just remember to upgrade every main item (weapon/implement, armor, neck slot) after level 1, 6, 11, 16, 21, 26. If this is taken care of, you can give other magic items.
Best Answer
Armored characters could afford plate armor faster
A step in an armored character's career is the purchase of a plate armor, which costs 1500gp. If you were handing out 10x the money, this would happen faster.
Potions of healing would be more common
Unlike most consumables, potions of healing can be bought for a listed price of 50gp. If money is very common then potions of healing will be too.
Spell components would be more available
Some spells require expensive material components. For example raise dead requires a diamond worth 500gp. If money were more available then these spells would be easier to cast.
Most other details depend on the DM's worldbuilding
There are no rules for buying magic items. If the DM is using the Sane Magic Item Prices pdf and allowing buying magic items, the group will soon have lots of magic items. If the DM doesn't allow buying magic items then the group won't be able to do this.
There are rules in Xanathar's for magic item crafting, but the rules expect you to go on quests to gather the components, and to spend weeks of time crafting the item. The rules include suggested gp costs, but the gp seems to be a small part of the total effort that goes into the item, and the DM could just charge more for the item if they wish.
The group might be able to live a lavish lifestyle, hiring servants to manage tasks for them. On the other hand, the DM might rule that everything costs 10x more in this world due to the higher availability of money, and in that case the group's lifestyle wouldn't change.