So in my brain I'm still thinking about buying the Spectre set without the tokens and just playing with them for a bit as I learn the rules. Reading other people's battle reports has given me ideas and me honestly pondering with myself I've realized that paper terrain and one starter set probably will suffice me for a long time as long as my terrain is varied and the scenarios are fun. I think i'll treat it more like a Role playing game as with those I only buy miniatures I absolutely need for a mission... hence why all my D&D guys are painted and only half of my war gaming collections (both the hobbit and warhammer 40k) are painted. I have no clue what setting I want my soldiers to be in. I've thought of the middle east or the jungles or doing the home front scenario (which I'd love to do). That's why I'm going to buy a couple more books and do research plus watch videos on some military and PMC groups today. One of them I remember was heading down to the islands in south america... jamacia? in order to stop a rise of terrorist attacks there before it got too big. If I find the video again I'll post it here. While most are in the middle east there are groups helping even in the US against the drug lords and gangs here. So there is a lot of options (especially the Ukraine crisis going on right now). So some books and videos should give me ideas.
Now for those of you wanting to get into this hobby and not do as I did with war hammer 40k I recommend these sites for possibly starting your army:
The Assault Group
Mike Bravo Miniatures
All of these have unique miniatures that would suit various needs of players. Some collections are bigger than others but, to my knowledge, they all are 28mm and work together well. Of course some of these websites also have their own rulesets if you want to try them out.
As I'm going through the same process as you I'm thinking of "What Area of Operations are my guys going to be in?". Now some miniatures will suit various places while others will only suit a few.
The next is terrain and I'd suggest picking up some 110lb weight 8.5x11 Cardstock and, if you don't have one, a printer as the Paper terrain out there is awesome. Once I've made some terrain I'll let you know what ones I like the best but there are so many and many free ones out there too! Get cardstock as it will create durable terrain.
Then after you've done these things you should be ready... and so should I once I get all these things ordered. I think I'll go with some sort of middle east or south american theme to it. Or maybe homefront if I can come up with a "plausable" scenario on how it all happened.
Anyways I hope my rambling goes to good use and helps you with your hobby.