RCX · 3803-1
LEGO 3803-1 Robotics Invention System Upgrade Kit (1.5)
New / sealed value$43.2473% above original retail
Original retail$24.99Launch price
Used value$35.89Current estimate
90-day trendN/A188 months recorded
PRICE GUIDE
Current LEGO 3803-1 values
Condition-specific market estimates compared with the original retail price.
New / sealed value
$43.24
+73% vs. retail
Used value
$35.89
$29.15 – $39.94
Original retail
$24.99
Launch price
Market values are estimates for the set condition shown; live retailer and marketplace prices may differ.
MARKET TREND
Price history
Source-reported monthly market closes through Aug 2026; these can differ from the current estimated market value.
Monthly close$48.4912 plotted months
Used value$35.89Current estimate
Used range$29.15 – $39.94Current low to high
Latest monthly close$48.49
Period low$44.57
Period high$54.11
Period change+0.7%
MARKET VALUE
Sealed price history
Latest
$48.49
+0.7% over period
View monthly price data
| Month | Open | Low | High | Close | Sales | Source |
|---|---|---|---|---|---|---|
| 2026-08 | $41.88 | $39.67 | $52.90 | $48.49 | N/A | Market data provider |
| 2026-07 | $42.90 | $41.34 | $50.68 | $47.57 | N/A | Market data provider |
| 2026-06 | $40.13 | $38.02 | $50.69 | $46.47 | N/A | Market data provider |
| 2026-05 | $42.79 | $41.24 | $50.55 | $47.44 | N/A | Market data provider |
| 2026-04 | $41.66 | $39.47 | $52.62 | $48.24 | N/A | Market data provider |
| 2026-03 | $40.19 | $38.73 | $47.48 | $44.57 | N/A | Market data provider |
| 2026-02 | $41.56 | $39.37 | $52.49 | $48.12 | N/A | Market data provider |
| 2026-01 | $42.57 | $41.03 | $50.29 | $47.20 | N/A | Market data provider |
| 2025-12 | $46.73 | $44.27 | $59.03 | $54.11 | N/A | Market data provider |
| 2025-11 | $45.35 | $43.70 | $53.57 | $50.28 | N/A | Market data provider |
| 2025-10 | $41.34 | $39.17 | $52.22 | $47.87 | N/A | Market data provider |
| 2025-09 | $43.43 | $41.85 | $51.30 | $48.15 | N/A | Market data provider |
VALUE OUTLOOK
Growth and retirement
Total growthN/ACurrent sealed value vs MSRP
Annual growthN/A12-month close change
1-year forecast$44.13+2.1%
5-year forecast$47.64+10.2%
5-year range$45.00 – $49.00Collected estimate
Used value range$29.15 – $39.94Observed market range
MethodSource-provided projectionDisplayed as collected; BrickPriceWatch does not recalculate it.
Forecast sourceMarket data providerSource attached to the forecast fields.
Recorded history188 monthsCurrent history coverage on BrickPriceWatch.
ConfidenceNot independently scoredA range appears only when the source supplies bounds.
Forecasts are directional estimates, not guaranteed future prices or investment advice. Actual value depends on condition, demand, fees, and sale timing.
Retired and sold as a retail-limited Mindstorms 1 accessory, Robotics Invention System Upgrade Kit is sought by early theme collectors for completeness, and its long-retired status and low remake risk have produced moderate post-retirement appreciation, while software dependence and lack of unique parts keep upside and resale stability constrained.
SET PRICE GUIDE
LEGO 3803-1 Robotics Invention System Upgrade Kit (1.5) price, value and history
LEGO 3803-1 Robotics Invention System Upgrade Kit (1.5) is a set released in 1999 in the RCX theme with 70 pieces. This BrickPriceWatch price guide combines a current new and sealed value of $43.24, an original retail price of $24.99, and 188 months of source-reported price history in USD.
The current comparison is based on collected market observations rather than a guaranteed selling price. The recorded used value is $35.89. The set is recorded as retired.
Current market dataa current new and sealed value of $43.24
Retail comparisonan original retail price of $24.99
Retailer availabilityno recent verified retailer quote; open the offer panel for the latest observed links.
How to use this LEGO price guide
Use the price guide to compare new and sealed value with the original retail price, inspect monthly high, low, and closing prices, and review current retailer offers before buying. Set condition, completeness, packaging, shipping, taxes, and marketplace timing can change the final price.
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