I would just like to get your opinion. I've been contemplating using static weapons and just play around with special features for their weapons. How do you guys feel about that? Or should I just let the player purchase new weapons?

It really depends. Personally, I use static weapons/armors (level up and special effects customization stay possible) and let the player buy accessories only.
What is really important is to find a balance between player development and equipment development. Buying weapons in stores happen to be an easy way to achieve that but is by no means the only way.

Use them sparingly. Accessories give the player more freedom when it comes to cool effects, but these things can add extra value to a weapon or armor. For example, you can't make Excalibur too statistically powerful, or it becomes unbalanced. However, if you give Excalibur an effect like "Does 1.5x damage to magical beings" (As with Chrono Trigger's Zanmato), it's both balanced and feels awesome. Same way in FFIV, where Cecil gets a weapon that has a chance of inflicting instant death on non-undead enemies. This feels like a special weapon and is rather balanced.

So, as my general rule of thumb, give it an effect if you want to make it feel special. Not "special", special.

I wouldn't dislike if instead of having different weapons with different characteristics, there were just one weapon that could be customized by the player.
It would fit in a game were weapons are story related and not just interchangeable tools, for example.

It depends entirely upon the set up. Static weapons has the downside that you lose one of the things you customize with your player, and if the game gets more difficult, the player loses one of the avenues of tackling problems and getting stronger. It can still work, but you have work around it.

i.e. does the weapon gets better over time? can you gain new abilities to work with it? etc.

Yeah, I really wanted to play around with giving their weapons abilities that will level up over time. Or play around with some kind of level up feature for the weapons, I just wasn't sure which would be better; because I know I love going to that new town and seeing what weapons and armor they have.

you could always just have the game do weapons normally, but then have certain skills be contingent upon a certain character equipping certain weapons.

i.e. say you got king arthur, who got the sword excalibur and another sword named "masterwork long sword", another weapon. excalibur's attack strength is calculated based on the level, and if king arthur is above level 10, 15, 20, and 30, he respectively unlocks healing spells, shielding spells, and other spells. So in the beginning, even though by the story's count, the player will have given excalibur already, they might not use that and opt for the masterwork longsword at the beginning of the game.

I'm glad I saw this topic because I had the same Idea for my rpg. The player had a static weapon but items/orbs that gave different elements and special affect (as previously stated) could be collected and equipped to the weapon.

Special affects like:

- Absorbs health per attack
- Does x2 damage when hp is less than 50%

You can even allow the weapon to level up and gain experience as the player levels up as in some mmorpg's I have seen.