C&C fan looking for a cheap and similar game to play during the evening for some relaxation... any suggestions from the site?
As I don't want to be spending a fortune!!

A strategy game for relaxation?!! No, I don't know any.

openra if you want something really, really similar (but not on this site): https://www.openra.net/


I think Empire at War could be BETTER then CnC: https://www.gog.com/en/game/star_wars_empire_at_war_gold_pack
Loria is more like Warcraft, but it's free: https://www.gog.com/en/game/loria

You never said how much or what specifically you like about CnC that you want in a strategy game.

I found Settlers to be a lot like Warcraft also.

The closest this shop has is:

https://www.gog.com/en/game/swine_hd_remaster
https://www.gog.com/en/game/supreme_commander_gold_edition
https://www.gog.com/en/game/supreme_commander_2
https://www.gog.com/en/game/act_of_war_gold_edition
https://www.gog.com/en/game/earth_2150_trilogy
https://www.gog.com/en/game/submarine_titans
https://www.gog.com/en/game/krush_kill_n_destroy_xtreme
https://www.gog.com/en/game/krush_kill_n_destroy_2_krossfire
https://www.gog.com/en/game/war_wind
https://www.gog.com/en/game/war_wind_ii_human_onslaught
https://www.gog.com/en/game/ashes_of_the_singularity_escalation
https://www.gog.com/en/game/dark_reign_expansion
https://www.gog.com/en/game/dark_reign_2
https://www.gog.com/en/game/tzar_the_burden_of_the_crown

The first 5 are my favorites, especially AoW. There are others but they usually involves more tactics and/or are in space.

Submarine Titans
8-Bit Armies ( CNC Clone )
Act of War ( Highly recommend )
Battle Realms Complete ( Will not work with two monitors turn on)
Dark Reign ( GOG updated the game to work on windows 10,11 now )
Dark Reign 2 ( Early 3D RTS that might be the relaxation you want )
Krush Kill 'N Destroy 1,2 ( Look them up)
NORTHGARD ( You can pass on all the DLC )
Original War ( Cheap and one my all time fav RTS )
Star Trek Armada 1,2 ( Space RTS )
Warriors Kings

I have been having issues with rivaTuner making some of my old games not work. So if you have it on, turn it off for old games. This as well.

Many good suggestions have already been made. Another good game that hasn't been mentioned yet is Impossible Creatures.

World in Conflict with one of the nuke mods.

I second this. Not only is it "similar" but it's free, as in free speech (and also as in free beer).

Since CnC is free, it's free as in food too. :)

buy the remastered version and go for all the achievements and unlocks.

on sale it gets down to USD$2 otherwise its usually $10-20

STAR WARS™ Empire at War: Gold Pack developed by Petroglyph Games Inc (not Lucas Arts), remnants of Westwood Studios' RTS wing.

https://www.gog.com/en/game/star_wars_empire_at_war_gold_pack

Z: The Game
https://www.gog.com/en/game/z

Z is a brilliant game, probably my favorite RTS after Dune 2. However I would not recommend playing the 2012 version which is a mobile port with altered interface and ruined mouse cursor. I'd recommend to buy the game (because reasons), then find the original Z (1996) game along with Z: Expansion Kit (1998) which was produced for Windows 95 by GT Interactive, get the community patch / engine to play the complete package.

Currently there are 2 source port engines available:

Zod Engine (latest 2018-01-14)
https://sourceforge.net/projects/zod/files/

https://zod.sourceforge.net/ - home page

ZED Online (latest 2021-06-06)
https://sourceforge.net/projects/zedonline/files/releases/

https://zzone.lewe.com/ - home page

The link above looks familiar somehow ;-)

To be honest, original versions of first C&C titles are freely available (as far as I know legally, since they were made free long ago, then removed from the publisher site but still available as mirror copies via digital magazines and download portals known to be usually reliable and without pirate content..it could be seen as shady but I don't really think so).
They need some work to run on later systems, maybe, since are in their win9X era form.

For example, GamePressure offers them for free.
There are the official newer versions with updated graphics and compatibility, from EA site, Origin Store.
And then there's OpenRA, a sort of remake (it's probably based on a redone code or from portions of the original code that were made open, plus different graphics, I don't know, I just suppose).
There's also a site (I don't know it's legal status, though) that offers C&C games and many modded version of them as an online service, C&C Net.org

Also, I think I'll try the older free title War Wind
https://www.gog.com/war_wind