SA consider VM’s profit

Profitv:=α l+e (1-α)l-(1-e)θ-k*(e*e)-cv
Profiti:=r(α l+cs)-(1-e)β(α l+cs)
Profits:=-α l+e(p(1+d-p)-(1-α)l)-cs -r(α l+cs)+(1-e)β(α l+cs)+γ(α l+e (1-α)l-(1-e)θ-k*(e*e)-cv)

e:=((l-l α+θ)/(2 k))
r:=((β (2 k-l+l α-θ))/(2 k))

Profits

D[%,p]

Solve[%==0,p]

D[Profits,l]

Solve[%==0,l]

l:=((-p-d p+(p^2)+2 k α+p α+d p α-(p^2) α-2 k α γ+θ-α θ-γ θ+α γ θ)/((((-1+α))^2) (-2+γ)))

p:=((1+d)/2)

l

Simplify[(1/((((-1+α))^2) (-2+γ)))((1/2) (-1-d)-(1/2) d (1+d)+(1/4) (((1+d))^2)+(1/2) (1+d) α+(1/2) d (1+d) α-(1/4) (((1+d))^2) α+2 k α-2 k α γ+θ-α θ-γ θ+α γ θ)]

l:=((-1+2 d (-1+α)+(d^2) (-1+α)+α-8 k α (-1+γ)+4 θ+4 α (-1+γ) θ-4 γ θ)/(4 (((-1+α))^2) (-2+γ)))

e

Simplify[%20]

r

Simplify[%22]

Δe:=((1-2 d (-1+α)-(d^2) (-1+α)+α (-1+8 k (-1+γ)-4 θ)+4 θ)/(8 k (-1+α) (-2+γ)))-((-1+2 d (-1+α)+(d^2) (-1+α)+α+8 k α-4 θ+4 α θ)/(16 k (-1+α)))

Δe

Simplify[((1-2 d (-1+α)-(d^2) (-1+α)+α (-1+8 k (-1+γ)-4 θ)+4 θ)/(8 k (-1+α) (-2+γ)))-((-1+2 d (-1+α)+(d^2) (-1+α)+α+8 k α-4 θ+4 α θ)/(16 k (-1+α)))]

Δl:=((-1+2 d (-1+α)+(d^2) (-1+α)+α-8 k α (-1+γ)+4 θ+4 α (-1+γ) θ-4 γ θ)/(4 (((-1+α))^2) (-2+γ)))-((1-2 d (-1+α)-(d^2) (-1+α)-4 θ+α (-1-8 k+4 θ))/(8 (((-1+α))^2)))

Δl

Simplify[((-1+2 d (-1+α)+(d^2) (-1+α)+α-8 k α (-1+γ)+4 θ+4 α (-1+γ) θ-4 γ θ)/(4 (((-1+α))^2) (-2+γ)))-((1-2 d (-1+α)-(d^2) (-1+α)-4 θ+α (-1-8 k+4 θ))/(8 (((-1+α))^2)))]

if SA want to build relationship with VM that she considers the VM’s profit when she fix the price: 
e = ((1-2 d (-1+α)-(d^2) (-1+α)+α (-1+8 k (-1+γ)-4 θ)+4 θ)/(8 k (-1+α) (-2+γ))), 
r = ((β (2 d (-1+α)+(d^2) (-1+α)-8 k (-2+α+γ)+(-1+α) (1+4 θ)))/(8 k (-1+α) (-2+γ))),
p =(( 1+d)/( 2)),
l = ((-1+2 d (-1+α)+(d^2) (-1+α)+α-8 k α (-1+γ)+4 θ+4 α (-1+γ) θ-4 γ θ)/(4 (((-1+α))^2) (-2+γ)))