There look to be a few very big spenders out there.
Brooklyn -- sits at $59.3 million committed to six players. They reportedly are making Brook Lopez a max offer ~$19 million in year 1) and Thaddeus Young an offer that pays about $12 mil. This takes them over $91 million, for 8 players. They will also pay about $1.3 million to their 1st round pick (Hollis-Jefferson), and have about $3 mil in non-guaranteed salaries to minimum players that they will probably all keep. That's $95 mil for 12 players. They extended Teletovic a qualifying offer of $4.2 mil, although he'll likely get an offer at the MLE of $5.46 million. They also have the taxpayer MLE of $3.37 million. If they matched Teletovic at the MLE and used their own MLE, they could be at around $104 million for 14 players, so an upper bound of about $105 million if they don't make any trades, and a lower-bound of $97 million, again assuming no trades.
Cleveland -- The Cavs have a ton of free agents, so who knows. But currently they have about $35 million committed to Irving, Varejao, Mozgov, Miller, and Joe Harris. LeBron, barring something crazy happening, will get $21.6 mil. Their stated goal is to also re-sign Thompson and Love, who are good for about $19 and $16 million, respectively. That's approaching $92 million for 8 players. They also have extended qualifying offers to Shumpert and Dellavedova -- I don't know what Cleveland's walk away price is from either, but for the sake of seeing how much they could spend, I'll suppose they'll pay $10 million to keep the pair. JR Smith is a free agent as well, and reportedly wants $8 million per year -- the Cavs can pay up to $8.9 million with his Early Bird rights. They also have the taxpayer MLE, and some second round picks to make the minimum. If they keep Smith at $8 million and use the MLE, they could hit $115 million. I think $105 million is more likely (no Smith), but it's hard to see them below $100 million if Love doesn't leave. They also have Brandon Haywood's non-guaranteed $10.5 million contract, which they are attempting to trade for either a trade exception or useful players from teams trying to clear payroll, which could again push their payroll even further.
Golden State -- They're at $83 million right now with Draymond Green still to pay. While it's likely that Lee will be traded when they give Green the max, if they can't find a partner, their payroll will spike to over $100 million, and could get near $105 if they use the MLE. (As a side note, keeping Lee will cost the Warriors over $30 million in luxury tax dollars on top of his $15.5 million salary. This is why they will be willing to give up assets to move his contract, and probably a pretty decent asset at that.)
LA Clippers -- They probably won't win the title for largest payroll this year, but they have an outside shot if Love leaves Cleveland and the Nets are able to dump a huge contract. Currently at $66 million with 8 players, keeping Jordan will put them at $85 million. They will use the taxpayer MLE, and should have no trouble getting to about $92-95 million after signing some minimum salaries.
Miami -- They're at $58.5 million owed to 12 players. Wade wants his $20 million and Dragic wants his $16 million. If they both get it, the Heat will be at around $95 million. If they look like they're keeping both at or near those asking prices, don't be surprised to see Miami dump a player or two, as they're in repeater tax territory this year.
Oklahoma City -- They've always been somewhat frugal. The question is will they spend this summer to show Durant they're willing to break the bank to win? They're at $77 million owed to 11 players. Kanter is a restricted free agent looking for the max -- if he gets that offer, will they match it and up their payroll to $93 million? Kyle Singler is also a restricted free agent -- his qualifying offer is $2.7 million, so they're at least willing to go that far with him. Would they go to $5 million? That gets them to $98 million. Cameron Payne is going to get $2 million as a draft pick. And they have the MLE to use too, as well as the Luke Ridnour trade exception they acquired yesterday ($2.75 million). $105 million is the upper limit, although it seems more likely they'll wind up closer to $95 million.
In summary:
Brooklyn -- $98-$105 million, unless they can dump one of Williams or Johnson.
Cleveland -- $100-$110 million, unless Love walks, in which case $95-105 million (since they can get some more salary using Haywood's contract).
Golden State -- $100-$105 million if they keep Lee, $85-$90 million if they don't (and they won't.)
LA Clippers -- $92-95 million if they keep Jordan, $76-$80 million if they don't.
Miami - $92-$95 million if they keep both Wade and Dragic and don't dump salary.
OKC - $100-$105 million if they keep their restricted free agents and don't make trades, but more likely $85-$90 million because they're still OKC.
My money is on Cleveland to have the highest payroll this year, but any of these 6 teams could pull it off, and the luxury tax bills this year could be very hefty.