There is a wait for MLD... but it is worth it provided you get your item in time and have the money. Ron is great, if there is a specific date you need something by, tell him and ask if that can be accommodated or not.
The $150 price point eliminates a fair number of options unless you go used / on sale. I don't know if they are still actively selling, but appytrails was selling a shaped tarp that was around $100. You might also want to think about bring a flat tarp that is sufficiently large for your needs. In good weather don't bother pitching or pitching open... do something more locked down if they weather is surprisingly bad.
I will note that the JMT, especially mid-summer, tends to have some of the mildest weather you might experience in alpine locations. It CAN storm, but typically not. More typical is dry except for condensation, with maybe a light, short lived rain in the late afternoon once you get on the east side. During the summer I tend to worry about the bugs more than rain. Some trips have been fairly bug free, but get there when the mosquitos are breeding in the snow melt and look out. The moment you stop moving, 100s (I have counted) can appear in less than a minute. If *I* was going to purchase a shelter just for the JMT and was trying to keep cost down (but exceed your $150 limit), I would go with the tarptent squall2.