If someone is bringing 100% of the money you are a property manager and not going to find anyone who wants to split equity with you just for telling them what to buy.
However, if you find a deal that costs 50k, manage a rehab for 40k, and refinance the house for 150k, then it's completely fair to expect to split the profit 50/50. In that case if you kept in 20% equity on a flip and hold, renting it out, Then it'd be perfectly fair to have 50/50 ownership.
As a rule, any dollar that a partner leaves in a deal is a dollar equal to his percent ownership, and you shouldn't expect to earn equity through sweat alone.
Most importantly, though, get documents, iron-clad documents that detail how your partnership will work, what happens when it ends, who gets what, how each partner gets what is owed and what the resolution of the partnership will look like. The more thorough this imagining is, the better your life will be. Every partnership ends, but not all partnerships end well. Make sure yours does! Best of luck!