Navagon: Company of Heroes - you can get this with the first expansion for very little and it remains one of the best games of its type out there. It is perhaps more focussed on tactics than strategy but it's a very well crafted game that should not be missed.

Total Annihilation - Very highly strategic featuring the planning possibilities and array of tactically versatile units that simply wasn't equalled until Supreme Commander came along. Arguably its spiritual successor is the superior game. But many prefer the pacing of TA over SupCom. I can only recommend both.

Dawn of War 1 & 2 - Both very different games with the sequel being entirely focussed on smaller scale tactical battles and the first one being much more about base building and larger scale conflict. Again both are good purchases depending on your tastes.

Total War - Many a Total War is less than $20 these days. I'd recommend Medieval 2 and Napoleon, personally. Empire, now that it's patched up, is very good too. But that one would be like throwing yourself in the deep end. That said there's a Emp + Nap pack that frequently retails for less than (the equivalent of) $20.

Men of War - if you like a challenge. A real bastard of a challenge posed by a very well crafted and surprisingly detailed game then Men of War isn't one to miss.

StonerMk2: Speaking of which ive seen a nearly limitless amount of Sins of a Solar Empire in my local Target for 10 bucks, perhaps i should pick that up since Impulse still sells it for 20 bucks. Anyone have any thoughts on Sins? Never played it but ive heard a lot of great things about it.

carnival73: With a little bit of research I have come to find that the "Rise of.." games are published through Microsoft, only sold hard copy and discontinued.

Xaromir: Something less based on fighting would be Anno, if you like such things.
There are a view so far, in chronological order:
1602, 1503, 1701, 1404.
Anno 1404 actually is the best but i came to hate ubi for their copy protection.
1602 and 1503 are quite tough in my opinion, 1701 is a bit half cooked, 1404 would be the best of both worlds though.

You can still build a little force and conquer enemy islands, but the main part really i discovering, building a city, becoming bigger and trading, you always have to see to it that there are enough supplies,
build supply routs and islands, find more efficient ways of building etc etc.
Diplomacy got more important with the "venice" addon, which adds the possibility, to claim an enemy island with money and diplomacy,
and establishing a majority in the islands city halls by buying into it.
You risk war by doing so but that's what diplomacy is for.
It also added spies and such, with which you can poison the enemies citizen etc.
The addon is included in the kings edition, which is somewhat beyond the budget but i recommend it.
The original should be available for about 25 and the kings edition for 35.
There also is a multi-player you can go in teams against the KI, or against eachother,
which i haven't tried.
If there is no kings edition or it's named differently, then that's because i freely translated the name.
It's a german game and i'm german so i never looked at the english version.
1503 is available here in the kings edition for 4euro used, but as i said, i found the first two quite hard,
and i'm with the series since the beginning, and consider myself a veteran.
They also don't have a multi player.
They all need a bit of time though.

Sorry if it may not fit your wish 100% but i thought i mention it,
because it's a bit different and not seen very often outside germany.

Bodkin: They are different.

First one is more shooting orientedy with a lot of guns.
Second is somewhere between.
Third is a lot about building bases with a hard combat and small numbers of soldiers. Kinda like Sims :)

USERNAME:carnival73#Q&_^Q&Q#GROUP:4#Q&_^Q&Q#LINK:38#Q&_^Q&Q#And what's with UFO Extraterrestials - is this even the same company that did the three here on GoG?#Q&_^Q&Q#LINK:38#Q&_^Q&Q#