This is my first try at building and constructing a budget 3 color deck on my own. Have a look, and if there's anything I can change to make it run smoother with some upgrade and sideboard ideas all the help would be greatly appreciated.
Welcome to MTGS. It's a good try for a first deck.
When building a deck, you want to try to put together cards that serve a similar theme and strategy.
For example, you have Scute Mob but only 19 lands. With so few lands, it will be very hard to get enough lands for Scute Mob's ability to work, so Scute Mob does not really fit into this deck. You have artifacts to help increase your mana but they do not increase your land count, so it does not help Scute Mob. The Mob is better in a different type of deck.
Invisible Stalker is a very fun card to kill people with, but it is also begging to be made bigger with Auras and Equipment. Because it is hexproof, it will not die easily, so it is safe to use other cards to make it bigger. Trepanation Blade is not very effective. Cards like Behemoth Sledge, Armadillo Cloak, and Invocation of Saint Traf are much better at making Invisible Stalker into a dangerous threat! You should try running something like that (or even Elephant Guide) instead of Trepanation Blade.
I don't understand what Bioshift is doing here. If you move the counter from Fleecemane Lion onto another creature, you don't make that other creature Monstrous or hexproof and indestructible. Bioshift only moves the +1/+1 counter, not any other abilities. You should probably remove it from your deck.
Fog is also not very good. It only protects you for one turn, but then you can still lose the next turn. Ghostly Prison is a much better strategy for defense. If you are playing multiplayer and want a Fog effect to surprise the opponent in case someone tries to kill you, at least play Moment's Peace, which is much better.
A pet card of mine (and a card I use in my casual 1v1 decks) is Stoic Angel. A 3/4 flying vigilance is good on it's own for the most part, but locking down your opponent's board is pretty powerful. Her vigilance let's you have at least one other person up to attack with as well. I run a few tap effects in my deck to pin down my opponent's creatures like Sleep, but there are plenty of others to choose from. The best part is I think Stoic Angel is around 50cents a piece online so she's an easy buy.
As suggested, I would cut the Fogs, Bioshifts, and Scute Mobs.
Articfacts:
2x Azorius Signet
2x Selesnya Signet
2x Simic Signet
4x Trepanation Blade
Planeswalker:
1x Elspeth, Knight-Errant
Instant:
2x Bioshift
3x Blinding Fog
3x Fog
3x Rootborn Defenses
2x Scavenging Ooze
3x Scute Mob
2x Fleecemane Lion
3x Jace's Phantasm
4x Invisible Stalker
Enchantment:
3x Ghostly Prison
2x Evolving Wilds
6x Forest
4x Island
7x Plains
When building a deck, you want to try to put together cards that serve a similar theme and strategy.
For example, you have Scute Mob but only 19 lands. With so few lands, it will be very hard to get enough lands for Scute Mob's ability to work, so Scute Mob does not really fit into this deck. You have artifacts to help increase your mana but they do not increase your land count, so it does not help Scute Mob. The Mob is better in a different type of deck.
Invisible Stalker is a very fun card to kill people with, but it is also begging to be made bigger with Auras and Equipment. Because it is hexproof, it will not die easily, so it is safe to use other cards to make it bigger. Trepanation Blade is not very effective. Cards like Behemoth Sledge, Armadillo Cloak, and Invocation of Saint Traf are much better at making Invisible Stalker into a dangerous threat! You should try running something like that (or even Elephant Guide) instead of Trepanation Blade.
I don't understand what Bioshift is doing here. If you move the counter from Fleecemane Lion onto another creature, you don't make that other creature Monstrous or hexproof and indestructible. Bioshift only moves the +1/+1 counter, not any other abilities. You should probably remove it from your deck.
Fog is also not very good. It only protects you for one turn, but then you can still lose the next turn. Ghostly Prison is a much better strategy for defense. If you are playing multiplayer and want a Fog effect to surprise the opponent in case someone tries to kill you, at least play Moment's Peace, which is much better.
Rootborn Defenses is not good here because you have nothing to populate. If you want a card to protect your creatures, consider Selfless Spirit, Dauntless Escort or Make a Stand.
As suggested, I would cut the Fogs, Bioshifts, and Scute Mobs.
Cards to look at:
Dunes of Zairo
SHANDALAR
Innistrad - The Darkest Night
~THE RAVNICAN CONSORTIUM~
A Community Set
Commander: Allies & Adversaries