Like Zouls I'm also not a fan of pay to skip or pay to geht more xp/gold items. Those are also pay to win for me cuz if you want to be the best as fast as possible then you have to buy them.
The only way I like such boost is how guild wars 2 handled then: Through a tradable cash-currency that was also obtainable ingame through other methods.
In guild wars there were gems that could be used to be stuff in the ingame store (like skins, boosts, repair kits (to repair without having to get to a city), companions (cosmetic) or more stashes in the inventory), but these gems could not only be bought by cash, but also traded through a ingame trader (where the price was set by offer and need between players) and also were obtained in pvp tournaments and some other situations (like doing dailies or with Achievements).
So if you add such items (what I hope you don't) let there be a way to get those without having to pay cash for them. Add a currency ingame like gw or let the items be tradable (may be only the boost or those other items that effect gameplay). I would go for the special currency which is tradable, cuz that would lead to more freedom and may be a better way to get the economy easier to handle. Also let us get those currency or items also ingame (on a more rare occasion) like through some daily todos or as rare loot on titans, hidden chests or as a rare resource found underground.
On this way you allow people to pay money if they want, but also give other players the possibility to get those items without paying (but through work). Also, on this way players with less time can trade them to get more ingame currency and players who play for long have another gold sink (if there is no gold boost ).
And ps: I played gw2 a lot a while ago and loved to spend some gold now and then for gems, on which way I supported others to be those gems with cash. So I also gave money to NCsoft without opening my wallet