For that kind of budget, there seem to really only be 2-3 choices for a pack from what I've seen. I'm a new member (joined around Christmas) so I may not have seen every option, nor have I looked into every pack build thread here. I'm also where you seem to be; I've got some decent tools, I don't mind going out to get one or two more, but I'm fairly new to prop-making so I'm cautious about how happy I will be with the final product after muddling through the project.
From my research, here's what I've found:
Option 1) You say you've got some solid tools and patience. Check out
Astyanax's Low-budget build. I think he totalled it to be about $450 USD before electronics and his aim was to use simple, inexpensive, easily-found materials with simple tools and techniques.
Option 2) For that price point, and an electronics-free kit,
Anovos is accepting pre-orders for kits at your price point exactly.
I had ordered one because it was a good price for what looks like a solid replica kit and they have payment plan options. Anovos has a pretty strong reputation with their Star Wars replicas. Many of their Star Trek and Battlestar Galactica offerings are really well done, too. I'm also a member of the
Starfleet 1701stforum and was looking into Anovos'
Monster Maroon. The 1701st had found a lot of little things that Anovos got wrong despite having access to "screen-used" assets, or there were flaws in production.
I was concerned that the pics they show are only of the prototype and not of the production unit. After discussing this, and Anovos in general with other members of both forums, I was also concerned that they sometimes seem to use the "pre-order" system as a way to crowd-fund the production of their wares rather than dumping money they already have into production but simply allowing customers to pay for theirs before the wares are ready for shipping. I did some more research into kits and finally decided to cancel my order.
Instead, I went with...
Option 3) BenofKent Props.
I went with Ben for a few reasons. 1) The price for the kit (as I want to actually assemble it myself and put my own finishing touches on it) isn't too far from the Anovos kit when you take currency conversions into account. 2) I follow BoK Props on Facebook and have had a chance to see the feedback he gets from customers, the skill and workmanship that goes into the packs and chat with him about the kits and his business in general. 3) I have confidence in his product; he's been making packs for over 10 years and distributing them to people all of the world. This means he's had plenty of opportunity to get feedback and make changes to build a better pack. They're con-tested and robust. His attention to detail and accuracy is also a big selling feature. I've also heard from a few personal friends that his stuff is great.
I haven't got his pack yet, but I've ordered one and am expecting it in the fall, so look for a build thread from me.
Anyway... enough "bashing" of Anovos and ego-stroking of Ben. If you go with Ben's kit, I think we'll both be extremely satisfied with our purchases.