One way to do so is add custom widget of Google Map, and add custom marker. Building custom marker having each prices is a bit complex, because it can be set as images.
As a reference(not tested):
Future<BitmapDescriptor> createCustomMarkerBitmap(String price) async {\n  final double width = 100.0;\n  final double height = 50.0;\n  final double cornerRadius = 4.0;\n\n  // Create a PictureRecorder\n  final ui.PictureRecorder pictureRecorder = ui.PictureRecorder();\n  final Canvas canvas = Canvas(pictureRecorder);\n  final Paint paint = Paint()..color = Colors.white;\n  final double pointerHeight = 10.0;\n\n  // Draw a rounded rectangle for the main shape\n  final RRect rect = RRect.fromRectAndRadius(\n    Rect.fromLTWH(0, 0, width, height),\n    Radius.circular(cornerRadius),\n  );\n  canvas.drawRRect(rect, paint);\n\n  // Draw the pointer (small triangle at the bottom center)\n  Path pointerPath = Path();\n  pointerPath.moveTo(width / 2 - 5, height); // Starting point\n  pointerPath.lineTo(width / 2 + 5, height); // Right side\n  pointerPath.lineTo(width / 2, height + pointerHeight); // Bottom point\n  pointerPath.close();\n  canvas.drawPath(pointerPath, paint);\n\n  // Draw the price text\n  TextPainter textPainter = TextPainter(\n    textDirection: TextDirection.ltr,\n    textAlign: TextAlign.center,\n    text: TextSpan(\n      text: '\\¥$price',\n      style: TextStyle(\n        fontSize: 16.0,\n        color: Colors.black,\n        fontWeight: FontWeight.bold,\n      ),\n    ),\n  );\n\n  textPainter.layout(minWidth: 0, maxWidth: width);\n  textPainter.paint(\n    canvas,\n    Offset(width / 2 - textPainter.width / 2, height / 2 - textPainter.height / 2),\n  );\n\n  // Create an image from the canvas drawing\n  final ui.Image image = await pictureRecorder\n      .endRecording()\n      .toImage(width.toInt(), (height + pointerHeight).toInt());\n  final ByteData? byteData = await image.toByteData(format: ui.ImageByteFormat.png);\n  final Uint8List pngBytes = byteData!.buffer.asUint8List();\n\n  return BitmapDescriptor.fromBytes(pngBytes);\n}\n\n// Setting Custom Marker\nFuture<void> addCustomMarker(GoogleMapController mapController) async {\n  BitmapDescriptor customIcon = await createCustomMarkerBitmap('1000'); // Specify price\n\n  Marker marker = Marker(\n    markerId: MarkerId('custom_marker'),\n    position: LatLng(35.6895, 139.6917), // Example position (Tokyo)\n    icon: customIcon,\n  );\n\n  setState(() {\n    markers.add(marker);\n  });\n}
Google map - Custom marker as component (Request Feature)
