Sponsorship outside of either Pro level is pretty rare. Generally any support packages will be assistance packages or "incentivised buying". These are generally agreements to buy products at a discounted price, but usually carry caveats to protect the supplier providing the discount. The supplier is agreeing to sell you something at a discount from his profit margin, so is going to rightly want something in return (I mean it's hardly a mass market and Piper has gotta eat). This can come in a number of guises, such as simply winning, to promotion, to public thanks, or more commonly exclusive and guaranteed sales. i.e. If you was to guarantee to purchase X cases a month from a specific supplier you would expect to receive an incentive for agreeing to do so. If the supplier has an idea of how much he needs to order in a monthly basis, he can save on his storage costs, seasonal demand variation and ultimately negotiate an agreement with the manufacturer for discounts on the cost price. Simple supply and demand economics and economies of scale. The more you order the bigger the discount you should expect.
Although a start-up team would be unlikely to qualify for big discounts (as there's always a getting to know your customer period), incentivised buying is generally going to be driven by guaranteed and volume sales only, and not the success rate of the team. Sinners, Monkey Love, Zone, Quake and many others are examples of this, all respectable at the local level but certainly not topflight driller killahs (although some players may move onto become one), however exclusive gun and paint deals, a good relationship with their suppliers (through prolonged purchasing probably at additional cost to the team), massaging of egos and an established profile will often open up "assistance" packages that are highly favourable to both the team and also the supplier.
There are always going to be good teams who attract additional support in the form of sponsorship (free or ridiculously priced stuff). This can either be on results or expected results. This is additional support and more akin to sponsorship. This is more expensive for the sponsored in the beginning, but possible results and subsequent publicity may lead to additional sales in the long term. Most teams will probably never attain such level and in all sports generally limited to the top levels
Of course there are exceptions to every rule, factory or exhibition teams, or teams / individuals no one in the right mind would want to associate with (L J). There are even altruist philanthropists out there (I think Yorkie at Tourney Park), but in general as in pretty much everything else, money is the deciding factor in all decisions, paintball despite it's size, is very bug business.
Therefore after my rambling, sponsorship or assistance is never a given, but think with your business head, and there's always a deal out there with your name on it.