Maximize u(x₁, x₂) = x₁^α x₂^(1-α) subject to the budget constraint, then add an upper limit on how much of one good is available.
max u s.t. p₁x₁ + p₂x₂ ≤ w
λ = ∂v/∂w is the marginal utility of income, and μ = ∂v/∂x̄ is the utility gained from one more unit of availability.