I'm looking for different satellite data concerning different scales. The first one I'm looking for is remote data for soil sealing and water bodies at a scale of 1:30,000, could be generally everywhere. The other one I'm looking for is for data with Mapping of parks in urban areas and the sub-classes: lawn, bushes, trees, tree groups, water bodies, lane (sealed) and lane (unsealed) at a scale of 1:5000. I was checking the page of USGS but it doesnt really provide a lot of satelitte data for the scales I am looking for. Could anybody recommend some descent pages where I can get this images without have to pay too high amounts to get the info?
As stated above, I'd try USGS Earth Explorer for data in the US. Your scales are pretty large. Especially 1:5000, for which you could look for 'Hi-Res Orthoimagery' with Earth Explorer. USDA NAIP imagery exists for almost everywhere in the US at 1 meter resolution. Historical imagery can be found on Earth Explorer as well. You could use the National Hydrography Dataset as well, for locating waterbodies (1:24000). National Land Cover Dataset may also be a resource you're interested in.
Hi res imagery may exist from your county, depending on where you are, so you might look in to that, though they sometimes charge you and don't make it publicly available.
You aren't looking for imagery with a specific scale of 1:30,000, it's just that you are trying to find imagery that has a spatial resolution that suits your needs. Check this page from ESRI and this page from NOAA. It's about what you need to get from the imagery and at what scale.
Earth Explorer allows you to select an area of interest. Then, click the 'data sets' tab, and choose the 'aerial imagery' drop down. you'll be given lots of options. Each option has a little info icon that can tell you more about the type of imagery. Choose some that you think will work and see if they are available for your area by clicking the 'results' tab. Like I said the NAIP JPG2000 might be of interest to you, as well as high the 'high resolution orthoimagery' tab. This is my first stop for general imagery.
Satellite imagery is generally not labelled according to potential mapping scale, due to the indirect relationship between the two concepts.
WR Tobler's rule of thumb is "divide the denominator of the map scale by 1,000 to get the detectable size in meters. The resolution is one half of this amount." For your scales, that would mean 2.5m resolution imagery for 1:5000 and 15m resolution for 1:30000.
As for freely available data, only a few countries provide such 2m resolution data, while the 15m resolution data could be pansharpend Landsat data. It is generally western countries that provide high resolution data freely to their citizens (and sometimes to everyone). USA has lots of data easily available, while the European countries have more convoluted data access schemes.
If your area of interest is not in one of the western countries that provide the high resolution data, you'll have to get it from commercial providers, such as DigitalGlobe or Airbus D&S, with prices in the range of 10 euro to 16 usd per square kilometer.