Start your save with some free stuff, and debuffs (all configurable).

Install

Install the latest version of SpaceCore.
Unzip the mod folder into Stardew Valley/Mods.
Run the game using SMAPI.

Use
When creating a save, check the New Game Plus checkbox above the advanced options button. When you start, you'll get a Legacy Token. Right click with it to spend your points! Leftover points give you gold. (Amount of points and gold per point configurable).

Most options are self-explanatory, though the "Horse" option gives you a flute and a token for a free stable.

You also start with Pierre's stock list and Ginger Island unlocked (configurable).

Certain penalties apply as well (though you can configure these to not do anything):

Profit margin is smaller.
Relationship point gains are less.
Experience needed for each level is increased.

Uninstall
Note: Price Multiplier will stay in effect after uninstallation. And of course your items won't disappear.

Compatibility
Compatible with Stardew Valley 1.5.5+ on Linux/macOS/Windows, both single-player and multiplayer.

See also