Public class Market {

[JsonProperty("id")]
public string Id { get; set; }

[JsonProperty("symbol")]
public string Symbol { get; set; }

/// <summary>
/// Name of cryptocurrency
/// </summary>
[JsonProperty("name")]
public string Name { get; set; }

/// <summary>
/// Image of cryptocurrency
/// </summary>
[JsonProperty("image")]
public Uri Image { get; set; }

/// <summary>
/// CurrentPrice of cryptocurrency
/// </summary>
[JsonProperty("current_price")]
public double CurrentPrice { get; set; }

/// <summary>
/// Рыночная капитализация
/// </summary>
[JsonProperty("market_cap")]
public long MarketCap { get; set; }

[JsonProperty("market_cap_rank")]
public long MarketCapRank { get; set; }

[JsonProperty("fully_diluted_valuation")]
public long? FullyDilutedValuation { get; set; }
/// <summary>
/// Объем(24 ч)
/// </summary>
[JsonProperty("total_volume")]
public long TotalVolume { get; set; }

[JsonProperty("high_24h")]
public double High24H { get; set; }

[JsonProperty("low_24h")]
public double Low24H { get; set; }

[JsonProperty("price_change_24h")]
public double PriceChange24H { get; set; }

[JsonProperty("price_change_percentage_24h")]
public double PriceChangePercentage24H { get; set; }

[JsonProperty("market_cap_change_24h")]
public double MarketCapChange24H { get; set; }

[JsonProperty("market_cap_change_percentage_24h")]
public double MarketCapChangePercentage24H { get; set; }

/// <summary>
/// Циркулирующее предложение
/// </summary>
[JsonProperty("circulating_supply")]
public double CirculatingSupply { get; set; }

[JsonProperty("total_supply")]
public double? TotalSupply { get; set; }

[JsonProperty("max_supply")]
public long? MaxSupply { get; set; }

[JsonProperty("ath")]
public double Ath { get; set; }

[JsonProperty("ath_change_percentage")]
public double AthChangePercentage { get; set; }

[JsonProperty("ath_date")]
public DateTimeOffset AthDate { get; set; }

[JsonProperty("atl")]
public double Atl { get; set; }

[JsonProperty("atl_change_percentage")]
public double AtlChangePercentage { get; set; }

[JsonProperty("atl_date")]
public DateTimeOffset AtlDate { get; set; }

[JsonProperty("roi")]
public Roi Roi { get; set; }

[JsonProperty("last_updated")]
public DateTimeOffset LastUpdated { get; set; }
}

Моя модель

public class Roi { [JsonProperty("times")] public double Times { get; set; } [JsonProperty("currency")] public string Currency { get; set; } [JsonProperty("percentage")] public double Percentage { get; set; } }