A Sane and Simple bitcoin Savings plan <https://bitcointalk.org/index.php?topic=345065.0>

bitcoin-rake-method.go

package main

import (
	"fmt"
	"log"
	"os"
	"strconv"

	krakenapi "github.com/beldur/kraken-go-api-client"
	"github.com/jedib0t/go-pretty/v6/table"
)

const initialBTC = 30.0
const multiplier = 2.0 // every time the price multiplies by this value, we rake
const rake = 0.20      // % rake

func main() {
	// Fetch current Bitcoin price
	btcPrice := FetchBitcoinPriceUSD()
	mbtcPrice := float64(int64(float64(btcPrice) / 1000))

	// Print initial net worth
	btcStashUSD := initialBTC * float64(btcPrice)
	fmt.Printf("Your initial USD net worth is: $%.2f.\n", btcStashUSD)
	// Print current mBTC price
	fmt.Printf("Current mBTC price: $%.0f.\n", mbtcPrice)
	// Print rake %
	fmt.Printf("Rake: %.0f%% every time the price x%.0f.\n", rake*100, multiplier)

	CalcRakeMethod(btcStashUSD, mbtcPrice, rake, multiplier)
}

func FetchBitcoinPriceUSD() float64 {
	api := krakenapi.New("", "")
	ticker, err := api.Ticker(krakenapi.XXBTZUSD)
	if err != nil {
		log.Fatal(err)
	}
	btcUSD, err := strconv.ParseFloat(ticker.XXBTZUSD.Close[0], 64)
	if err != nil {
		log.Fatal(err)
	}
	return btcUSD
}

func CalcRakeMethod(netWorth, initialPriceMbtc, rake, multiplier float64) {
	t := table.NewWriter()
	t.SetOutputMirror(os.Stdout)
	t.AppendHeader(table.Row{"mBTC/USD", "BTC/USD", "mBTC holdings", "mBTC cashed out", "USD cashed out"})
	t.SetStyle(table.StyleBold)

	mbtcPrice := initialPriceMbtc
	mbtcInvested := netWorth / initialPriceMbtc // Assuming we invest all in the beginning
	totalRakedUSD := 0.0
	totalRakedMBTC := 0.0
	for {
		mbtcPrice *= multiplier
		rakedAmount := mbtcInvested * rake
		totalRakedMBTC += rakedAmount
		rakedAmountUSD := rakedAmount * mbtcPrice
		totalRakedUSD += rakedAmountUSD
		mbtcInvested -= rakedAmount
		t.AppendRow(
			[]interface{}{
				fmt.Sprintf("$%.0f", mbtcPrice),
				fmt.Sprintf("$%.0f", mbtcPrice*1000),
				fmt.Sprintf("%.2fmBTC", mbtcInvested),
				fmt.Sprintf("%.2fmBTC", rakedAmount),
				fmt.Sprintf("$%.2f", rakedAmountUSD),
			},
		)
		if mbtcPrice >= 1000 {
			break // stop if mBTC >= $1k (the plan ends there because the world will look very much different by then)
		}
	}
	t.Render()

	// Print final results (total raked amount in USD and mBTC, and mBTC left over)
	t2 := table.NewWriter()
	t2.SetOutputMirror(os.Stdout)
	t2.AppendHeader(table.Row{"USD Total raked", "mBTC Total raked", "mBTC Leftover"})
	t2.SetStyle(table.StyleBold)
	t2.AppendRow(
		[]interface{}{
			fmt.Sprintf("$%.2f", totalRakedUSD),
			fmt.Sprintf("%.2fmBTC", totalRakedMBTC),
			fmt.Sprintf("%.2fmBTC", mbtcInvested),
		},
	)
	t2.Render()
}

output.txt

Your initial USD net worth is: $1029597.00.
Current mBTC price: $34.
Rake: 20% every time the price x2.
┏━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ MBTC/USD ┃ BTC/USD  ┃ MBTC HOLDINGS ┃ MBTC CASHED OUT ┃ USD CASHED OUT ┃
┣━━━━━━━━━━╋━━━━━━━━━━╋━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━┫
┃ $68      ┃ $68000   ┃ 24225.81mBTC  ┃ 6056.45mBTC     ┃ $411838.80     ┃
┃ $136     ┃ $136000  ┃ 19380.65mBTC  ┃ 4845.16mBTC     ┃ $658942.08     ┃
┃ $272     ┃ $272000  ┃ 15504.52mBTC  ┃ 3876.13mBTC     ┃ $1054307.33    ┃
┃ $544     ┃ $544000  ┃ 12403.62mBTC  ┃ 3100.90mBTC     ┃ $1686891.72    ┃
┃ $1088    ┃ $1088000 ┃ 9922.89mBTC   ┃ 2480.72mBTC     ┃ $2699026.76    ┃
┗━━━━━━━━━━┻━━━━━━━━━━┻━━━━━━━━━━━━━━━┻━━━━━━━━━━━━━━━━━┻━━━━━━━━━━━━━━━━┛
┏━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┓
┃ USD TOTAL RAKED ┃ MBTC TOTAL RAKED ┃ MBTC LEFTOVER ┃
┣━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━┫
┃ $6511006.69     ┃ 20359.37mBTC     ┃ 9922.89mBTC   ┃
┗━━━━━━━━━━━━━━━━━┻━━━━━━━━━━━━━━━━━━┻━━━━━━━━━━━━━━━┛